The nesting behavior of Trachypus petiolatus is described from central Panamá. Females nested within aggregations in bare soil; they re-used nests from a prior generation, and provisioned their nests with small bees, mainly Apidae and Halictidae. These nests had a communal social organization among resident females, and also included one or more males. At least some males left the nest in the morning on a daily basis, and then returned later in the day. Based on limited nest excavations, we did not observe any parasitized cells, which may be associated with communal nesting.

Dolichurus heevansi, new species, is described from Baltic amber (Middle Eocene). It is the first fossil representative of a modern day genus in Ampulicidae. Putative relationships of D. heevansi with recent Dolichurus and fossil Ampulicidae are discussed. The taxonomic status of all known fossil Ampulicidae is evaluated.

Loss of the queen is a crisis for a social insect colony. The process of queen succession could cause increased aggression and work inefficiencies, and the new queen, if the colony can produce one, could be slow to develop mature eggs. We evaluated the cost of queen replacement in Polistes dominulus by removing the queen from a set of single-foundress colonies while leaving a control set with their queens. At 2 and 11 days after queen removal, we found that the queenless colonies had increased levels of some dominance behaviors, chewing and climbing, but not of the far more common lunging and biting. However, foraging behavior did not decrease on nests without queens as compared to nests with their original queens. Nest growth diminished as compared to control nests, as would be expected if new queens were not as competent at egg laying or if dominance behavior interfered with nurturing activities. Furthermore, replacement queens did not mate in the first 12 days after queen removal and few had mature eggs in their ovaries, though after a month most had mated and had developed ovaries. The degree of ovarian dominance of the top egg-layer over the others was also diminished at 12 days, but by a month the new queen was as dominant as control queens. The high cost of replacing the queen may indicate that workers are kept reproductively suppressed enough not to be a threat to the existing queen.

We record 16 species of spider wasps from Puerto Rico. One new species, Auplopus taino (Pepsinae), is described from a single female. The types of the long unrecognized Pompilus cressoni Dewitz, 1881 have been examined and found to be a species of Episyron, a genus not previously reported from Puerto Rico; E. cressoni is a senior synonym of E. conterminus posterus (W. Fox, 1893), a common North American species. Batazonus hookeri and B. mundiformis, now placed in Poecilopompilus and both described by Rohwer, 1915, are opposite sexes of a single taxon; P. hookeri has page priority. We here treat this wasp as a subspecies of the widespread Neotropical species, P. flavopictus (F. Smith, 1862).

Keys in both English and Spanish are provided for the separation of the known species, as are appropriate illustrations.

Pseudoscolia aequatoria, new species, from Archer's Post, Kenya, is the first sub-Saharan member of the genus. It is not closely related to any previously described North African species.

Machaerothrix tsushimensis Yasumatsu exhibits several previously undescribed characteristics in its behavior. The nest is composed of barrel-shaped cells and an outer covering. Before hunting females recondition old cells for reuse, by scraping dried mud from the nest surface with their mandibles, adding water, and working it into a soft ball, which is then daubed with the dorsal tip of the gaster. They capture salticid spiders and store them in the clay nests. The female amputates part or all of the spider's legs and walks forward, straddling the spider, holding it venter up by the spinnerets. Several females live together on the same nest for some period. They are usually tolerant of one another, though dominance interactions are found among them. The dominant female exhibits a full sequence of nesting behavior, including cell provisioning, but the subordinate tends to spend much time in resting on the nest. There is evidence that some of the subordinates initiate nesting activities on the nest where they have cohabited with the dominant, after the disappearance of the latter, or construct a new nest independently after cohabiting with the dominant. Prey stealing and cooperative nest construction and defence were observed. Nesting and social behaviors of this species are compared with those of other primitively social pompilids and the possible position of this species in the evolution of social behavior is discussed.

Tarantula hawk wasps in the genera Pepsis and Hemipepsis are conspicuous elements of Southwestern U. S. and the Neotropics where they often appear oblivious to potential predators while they actively forage for nectar or search for prey. Tarantula hawks produce large quantities of venom and their stings produce immediate, intense, excruciating short term pain in envenomed humans. Although the instantaneous pain of a tarantula hawk sting is the greatest recorded for any stinging insect, the venom itself lacks meaningful vertebrate toxicity. The respective lethalities of 65 and 120 mg/kg in mice for the venoms of Pepsis formosa pattoni and P. thisbe reveal that the defensive value of stings and venom of these species is based entirely upon pain. This pain confers near absolute protection from vertebrate predators. The pain also forms an enabling basis for the evolution of aposematic coloration, aposematic odor, and a huge mimicry complex involving most species of tarantula hawks and numerous flies, beetles, moths, acridid grasshoppers, and other Hymenoptera. Tarantula hawks form mixed-species, both-sex aggregations that appear defensive in nature and likely aid in the location of resources and mating opportunities for some species. Because tarantula hawks have no meaningful predators, selection pressure appears to have favored long life spans. Long-lived individuals may then function as aposematic models; thereby decreasing predatory attacks by vertebrate predators directed toward wasp kin and future offspring. This suite of defensive adaptations has enabled tarantula hawks to forage and behave with near impunity and to maximize their food and reproduction while having long adult lives virtually free from predation.

Compared to other ensiferan Orthoptera such as true crickets (Gryllidae) and katydids (Tettigoniidae) relatively little is known about the reproductive behavior of Anostostomatidae (formerly Stenopelmatidae), the king crickets, weta and allies. Moreover, although the New Zealand species (the weta) are best known, there is little knowledge of the biology of ground weta (Hemiandrus species), a variable genus especially with regard to ovipositor length. This paper presents observations of mating and post-mating behavior of several Hemiandrus species with short ovipositors. Sexually active males and females drum their abdomens on the substrate, apparently as local signals for mate attraction (pheromones may be involved in long distance communication). After mating there is both maternal and paternal investment. Females provide care to eggs and young larvae and males provide a spermatophylax to the female, a mating meal that, in other ensiferan Orthoptera can be an important source of nutrition. In contrast to other ensiferans, however, the spermatophylax of Hemiandrus species with short ovipositors is deposited on the female's abdomen, a separate location from the sperm ampulla. The spermatophylax is deposited while the male is attached to the female's underside, apparently to her modified 6^th abdominal sternite. Also, in contrast to related taxa, males remain with their mates while the mating meal is eaten. These observations indicate that ground weta are excellent systems for examining behavioral and ecological questions about the evolution of complex signals, as well as the evolution of maternal and paternal investment.

In most species of social insects, the nest is enlarged gradually as the colony grows. Here we call attention to some striking exceptions to this general rule of continuous nest construction. A common pattern among the swarm-founding, eusocial wasp species is explosive nest construction, in which the nest is built rapidly to a large size in the first one to three weeks after colony initiation. Nest size then remains static for weeks or months. We document this pattern of nest growth for the swarm-founding wasp, Polybia occidentalis. Data showing a high percentage of empty cells in pre-emergence-stage nests suggest that a similar pattern holds for some other swarm-founding polistine genera. In contrast, certain other genera seem to follow the continuous construction pattern of the independent founders. We propose five potential factors that could favor a strategy of explosive nest construction: maximization of colony productivity, work-group efficiency, protection of the brood, protection of the swarm adults, and enhancement of reproductive competition. We discuss evidence from both groups of swarm founders that provides circumstantial support for some of these, but not for others.

Previous authors have called attention to nest form variation between and within species of the Neotropical swarm-founding polistine wasp genus Parachartergus. One author characterized nests oriented horizontally and having the nest comb petiole central and in-line with nest cells as anomalous, and he suggested that anomalous nests constrain colonies from successful reproduction. We report two distinct nest forms of Parachartergus amazonensis (Ducke), one of which was oriented primarily horizontally and one only vertically, from a single locality in Peru. Horizontal and vertical nests, with corresponding difference in orientation of nest comb petioles, have additionally been observed in P. fulgidipennis (de Saussure) in Peru and Brazil and P. griseus (Fox) in Brazil and French Guiana. Nest orientation and comb petiole placement in these Parachartergus species may reflect a labile trait that is variably expressed as a function of availability of suitable nest sites. “Anomalous” nests may not constrain colonies from successful reproduction.

Over a five year period, 419 nests of Mischocyttarus collarellus were found on 128 structures in and around La Selva biological research station in Costa Rica. The nest of this species is different from that of many other independent-founding polistines, in that it has a distinctly horizontal petiole and outward-facing cells (rather than a vertical petiole and downward-facing cells). Nests were sometimes situated on vertical surfaces, but were most often attached to the underside of a substrate leaning up to 20° from vertical. A few nests (about 6%) were found on buildings, but most were found on trees with smooth, peeling, or flaking bark. The four tree species found most commonly to bear nests were Psidium guajava, Cecropia obtusifolia, Vochysia guatemalensis, and Bactris gasipaes. Nests were found on tree trunks and primary branches, never on foliage or twigs. Median nest heights above ground were 250–350 cm, ranging from under 50 to over 850 cm. A systematic search of trees in an area of known high nest density demonstrated that even experienced searchers may miss at least 27% of nests in a given area. Nests were never found to reach densities greater than 54 nests/hectare or occupy more than about 12% of apparently possible nesting structures, even in a stand of a preferred tree species.

Differences between castes and related aspects in Parachartegus fraternus (Gribodo) have been studied in various stages of the colony cycle. Five colonies from three colony development stages (namely, pre-emergence, worker-producing and male-producing) were analyzed. The main results were: irrespective of colony age, castes were always morphologically indistinguishable; non-inseminated ovary-developed females were found in four colonies; because differences of castes were physiological rather than morphological, castes are evidently post-imaginally determined and this is probably taking place according to the colony conditions. These findings support the occurrence of caste totipotency in Parachartergus fraternus.

Previous studies of the obligately eusocial sweat bee Halictus ligatus Say, at a nesting aggregation in Victoria, southern Ontario, Canada, showed how changes in local environmental conditions led to marked variation in demography, body size, and social patterns. Under the harsher weather conditions of 1990, mortality was higher, colony sizes were lower, brood body sizes were smaller, and surviving colonies were more strongly eusocial than under the milder conditions of 1991. These patterns suggested that the link between environmental conditions and colony social organization might be mediated by foraging effort, especially by queens during late spring and early summer when colonies were most susceptible to environmental constraints. Social parameters such as differences in reproductive effort between queens and workers or between haplometrotic and pleometrotic colonies, might also have a basis in differences in foraging effort. In this paper, I examine annual, seasonal, and social sources of variation in foraging effort of female H. ligatus from Victoria. Foraging effort of queens and workers was described in terms of seven different measures: number of foraging trips per day, flight time per trip, handling time per trip, average round trip time, total flight time per day, total handling time per day, and total provisioning time per day. These parameters were measured by observing individually marked queens and workers during their respective foraging periods in 1990 and 1991. Previously, it had been shown that in 1990 there were fewer days with weather suitable for flying, but observations of foraging effort show that the relatively large queens of 1990 spent about as much time foraging as the relatively small queens of 1991, and still produced much smaller brood. This suggests that a previously unsuspected effect of the poor weather in 1990 colonies was a scarcity of pollen, at least during the queen foraging period. Both queens and workers appear able to adjust their foraging effort to current conditions. As a result, the expected correlation between increased degree of eusociality (reproductive skew more strongly favouring queens) and stronger division of labour (workers doing a greater share of colony parental investment) did not occur, as workers apparently worked harder when their own reproductive opportunities increased. This may be a general pattern in social halictids.

Many insect species show intraspecific variation in their life-history patterns. Such variability may affect a wide range of traits including size, social behavior, sex ratios, mating tactics, and competition for resources; it may also affect population dynamics and interactions with parasites and prey. Trypoxylon politum has a seasonally variable, partially bivoltine life history (i.e., some wasps produce offspring that emerge before the end of June whereas others produce overwintering offspring) in the southern part of its range and a univoltine life history (one generation per year) north of central Virginia. Wasps from three partially bivoltine populations differ in the pattern of adult emergence, suggesting a latitudinal gradient in their responsiveness to photoperiod and other environmental cues affecting diapause. Wasp size, sex, the date on which the egg was laid, and rearing conditions also affect diapause and the timing of adult emergence. Few behavioral differences were found between wasps from Florida partially bivoltine populations and wasps from New Jersey univoltine populations, but their life histories and patterns of adult emergence differ markedly. When wasps from partially bivoltine populations are reared in the north (NJ), they emerge at the same time as local wasps. When wasps from univoltine populations are subjected to warm winter conditions (FL) they show a bimodal pattern of adult emergence: some emerge slightly later than wasps from partially bivoltine populations reared under the same conditions whereas others emerge at the same time as those developing in the north. This suggests variability in the effect of environmental cues on diapause and adaptation to local environmental conditions. The advantages of different emergence patterns are discussed in terms of their effect in avoiding unfavorable conditions such as freezing, and in taking advantage of favorable conditions such as synchronizing emergence with the occurrence of appropriate prey resources.

Synagris wasps (Hymenoptera: Vespidae: Eumeninae) include some of the most spectacular examples of exaggerated secondary sexual “weapons” known. I examined the scaling relationship between tusk length and head width in S. cornuta, a widely distributed, Afrotropical species. Data from museum collections and field observations demonstrate that, unlike most aculeate Hymenoptera, males of S. cornuta are larger, on average, than females and are dimorphic for mandibular tusk length with a discontinuous scaling relationship shape for head width. Other measures of body size are also examined. I also studied female nesting behavior and male behavior in the field in Côte d'Ivoire, West Africa. Nests and nest construction and other female behaviors are described. Most nests were constructed on the undersides of leaves of Aframomum latifolium Afz. (Zingiberaceae) using soil from termite tunnels or old S. cornuta nests moistened with water from leaves. As reported by previous authors, females progressively provision larvae and macerate pieces of caterpillar before feeding it to larvae. Larval silk attached to the leaf through an opening left by the mother may extend the lifetime of nests. Most nests included 1–3 cells and may be limited in size due to weight on leaves. Occupants of a high proportion of nest cells failed to emerge due to parasitism by rhipiphorid beetles and loss of nests. Males displayed trap-lining behavior, patrolling from nest to nest. Some tusked males guarded nests for periods of hours a day over several days. Males used their tusks in male-male competition over mud nest cells containing females about to emerge and also wielded them conspicuously in threat displays. Other males remained nearby and flew up to confront guard males. Unarmed (tuskless) males are less common and were not observed to guard. Some Synagris species show large weapons that are probably intrasexually dimorphic, while others simply show unusual mandibular development and still others lack weapons entirely. Depending on species, males are smaller than, equal to, or larger than females.

Information is presented on the previously unstudied digger wasp, Chlorion cyaneum (Dalhbom), obtained from 21 nests in central Texas. Nests were dug in partially shaded sandy soil and had 1–3 cells, each mass-provisioned with 1–9 Arenivaga bolliana (Saussure), (Blattaria: Polyphagidae). Prey were generally transported on the ground, grasped dorsum-up with the mandibles and forelegs. Wasps maintained both outer and inner nest closures when hunting. Arrangement of prey, degree of paralysis, and egg placement were similar to those reported for C. aerarium Patton. Cocoon structure is described for the first time for Chlorion. Comparisons of nesting behavior components with those reported for C. aerarium are presented and discussed.

Aspects of nesting biology of the widely distributed oriental solitary wasp Pison argentatum Shuckard are reported from five localities in the Philippines and one in Borneo. Completed nests comprised 1–9 cells, with average nest size differing between localities and nest substrates. Nests based on hanging roots tended to be heavily plastered with mud pellets, while those on human-made substrates were seldom plastered. Fully provisioned cells contained 7–21 spider prey. Over 75% of the 1003 prey recovered were Salticidae, while about 2% were Araneidae, the first web-building spiders recorded as P. argentatum prey. The remaining spiders were Lycosidae and Oxyopidae, like Salticidae mostly long-sighted non-web-building hunters, but also new prey family records for this wasp. P. argentatum offspring from three samples showed sex ratios (male/female) of 0.41, 1.53 and 2.40.

Seven nests of Abispa australiana (Mitchell) from Kakadu National Park, Northern Territory, two nests of A. splendida splendida (Guérin-Méneville) from Magnetic Island National Park, Queensland, and one nest of A. meadewaldoensis Perkins from Kununurra, West Australia constitute the most extensive sample of Abispa nests yet reported. The isolated, cryptic, mud nests had thick walls (up to 16 mm), a downward-pointing, funnel-shaped entrance tube, and an exterior plastered with numerous small mud pellets that matched substrate color. All nests were affixed to firm surfaces in semi-sheltered positions; the nest of A. meadewaldoensis was in a crevice below ground. For A. australiana, the largest nest measured 15.6 cm long × 6.9 cm wide × 4.5 cm deep, and comprised seven cells; cell dimensions averaged 33.8 mm long × 13.9 mm diameter. Females of all species appear to specialize on a few species of small pyralid or gelechiid caterpillars, provisioning cells with up to 79 prey. All 88 prey recovered from three cells of two A. australiana nests proved to be a single species of gelechiid. Provisioning type appears to differ among the three species, with A. s. splendida practicing progressive provisioning and A. meadewaldoensis and A. australiana being mass provisioners. Parasitism levels were low, with only two of 21 cells in the seven active nests attacked by an unidentified chrysidid. Unidentified sarcophagid and bombyliid fly remains were found in three previously emerged old nests; in two of these, the thick mud walls prevented sarcophagids from escaping. Both sexes were present at two A. australiana nests and one A. s. splendida nest, suggesting a wait-at-the-nest mating tactic in addition to scramble competition at water sources and nest trap-lining previously reported for A. ephippium. Another A. australiana nest found with two associated females may have been communal.

Males and females of Anthophora walteri Gonzalez, new species, from the Eastern Andes of Colombia are described and illustrated. The pupa is described, and information on the nesting behavior, natural enemies and host plants of this species are also given. Females of A. walteri can be distinguished from other Neotropical Anthophora by the predominantly white pubescence on the head and mesosoma, and orange setae on the metasoma which are denser and posteriorly-directed on apical margins of terga, thus forming apical bands. Males can be recognized by the sparse pubescence on the metasoma and the translucent apical margins of terga one to six. Bees nested in flat ground or small banks in very hard soils of semiarid and highly disturbed areas above 2500 m; nest entrances lacked turrets and cells were arranged in linear series as reported for other Mystacanthophora species. Pollen taken from nest cells was almost exclusively (>95%) from a single species of Lamiaceae (Salvia bogotensis). Adults of A. walteri fly from about October at least through July. Presumably immatures spend most of the year as postdefecating larvae and the period of adult emergence corresponds with blooming of S. bogotensis and the second peak of maximum rain in October.

Resumen: Hembras y machos de Anthophora walteri Gonzalez, especie nueva, de la cordillera Oriental de Colombia son descritos e ilustrados. La pupa también se describe y se presenta información sobre la biología de nidificación, enemigos naturales y plantas hospederas de esta especie. Las hembras de A. walteri pueden distinguirse de otras Anthophora neotropicales por la pubescencia predominantemente blanca en la cabeza y mesosoma, y las setas anaranjadas sobre el metasoma, las cuales son densas y están dirigidas posteriormente sobre las márgenes apicales de los tergos y por lo tanto formando bandas apicales. Los machos pueden reconocerse por la pubescencia esparcida del metasoma y las márgenes apicales translucidas de los tergos uno a seis. Las abejas nidifican en superficies planas o en pequeños barrancos de suelos muy duros, en áreas semiáridas y altamente perturbadas por encima de los 2500 m; las entradas de los nidos carecen de torres y las celdas están dispuestas en series lineares como ha sido registrado para otras especies del subgénero Mystacanthophora. Las muestras de polen tomadas de las celdas contenían casi exclusivamente (>95%) polen de una sola especie de Lamiaceae (Salvia bogotensis). Los adultos de A. walteri vuelan desde alrededor de Octubre, por lo menos, hasta Julio. Probablemente los inmaduros pasan la mayor parte del año como larvas posdefecantes y el periodo de la emergencia de los adultos corresponde con la floración de S. bogotensis y el segundo pico de máxima lluvia en Octubre.

The tropical stingless bees are known to use diverse nest sites, and some species will nest within the nest of other insects including ants and termites. However, it has not been reported before that a stingless bee, Trigona cilipes (Fabricius) (Hymenoptera: Apidae), is able to establish its nest within the nest of the social paper wasp Epipona tatua (Cuvier) (Hymenoptera: Vespidae) as reported here. The bell-shaped nest with both wasps and bees was found in secondary forest in Peru, and held under observation for several weeks until collection. Description of nest architecture and some behavioral observations are presented. Trigona cilipes is usually found nesting with Azteca ants, and the behavioral flexibility that enables them to also colonize wasp nests results in several advantages that may favor wasp associations as discussed in the text.

A comparative overview of flower visiting by non-Apis bees in the semi-arid to arid areas of southern Africa is presented. This is based on a survey of non-Apis bees and aculeate wasps in these areas. Flower visiting records (16,229) were assembled for 420 species of bees, 375 species of non-masarine wasps and 129 species of masarine wasps. Thirty six plant families were included. Of these 34 were visited by non-Apis bees, 28 by non-masarine wasps, and 22 by masarine wasps. In decreasing order, the ten families which received visits from the highest percentages of species of bees are: Fabaceae, Asteraceae, Aizoaceae, Zygophyllaceae, Lamiaceae, Malvaceae, Acanthaceae, Boraginaceae, Scrophulariaceae, and Brassicaceae. Most bee species visiting Fabaceae visit Papilionoideae unlike wasps, of which most visiting Fabaceae visit Mimosoideae. In the analysis bees overall show a high diversity of flower family choice at the specific level similar to that of non-masarine wasps. All bee families show a range from oligophagy or from narrow polyphagy to relatively broad polyphagy. No species are indiscriminately polyphagous. Two bee families, Colletidae and Melittidae, show a diversity of choice at the specific level lower than that of the other bee families and similar to that shown by masarine wasps. This suggests, for these two families, a relatively high incidence of oligophagy equivalent to that shown by Masarinae.

We examined the composition of pollen loads of female alfalfa leafcutting bees (Megachile rotundata) at a location where a variety of flowering plants were available, but where alfalfa (Medicago sativa) provided the vast majority of flowers. All females carried alfalfa pollen. Based on counts of pollen grains, pollen loads were greater than 90% alfalfa on three-quarters of the females collected in July and on nearly two-thirds of those collected in August. A single non-alfalfa pollen made up the majority of the loads on just 6% of females. The most common alternative pollen sources were yellow sweetclover (Melilotus officinalis), and Brassicaceae and Chenopodaceae whose pollens we could not distinguish at the species level. In both July and August, the diversity of pollen types on females was positively correlated with flower diversity within 50 m of shelters. This and other studies indicate that M. rotundata is an opportunist capable of exploiting a variety of plant taxa and flowers of different structure.

Wasp ichnofossils are scarce in the record because of their low preservational potential. Evidence comprises perforations in bee cells, cocoons, and paper and mud nests, whose preservation may involve the most unusual taphonomic processes. The record includes trace fossils preserved in other trace fossils; paper nests preserved in amber, ironstones and caves; and fragile trace fossils preserved in conglomerates. Evidence for wasps is weak in some cases and more reliable in others. Perforations in bee cells can be attributed to other insects; likewise cocoons can be attributed to other insects and other organic and inorganic processes. Some fossil paper and mud nests are the most reliable wasp ichnofossils. Brownichnus favosites preserved in ironstone and in Dominican amber, provide the oldest records of polistines known. One of the best-known examples of wasp ichnofossils is Chubutolithes gaimanensis, preserved in intraclast conglomerates. New ichnological and sedimentological evidence suggests that cells were constructed around plant stems from which they could have dropped to the soil, been covered with sediments, impregnated with carbonate, and then reworked by fluvial action along with other carbonate nodules.

Torymus evansi Grissell, new species, is described, illustrated, and compared to other Nearctic species of the genus. Morphologically it is intermediate between the varians and tubicola species groups. Torymus evansi is associated with rearings of Dactylopius sp. (Hemiptera: Dactylopiidae) on Opuntia sp. (Cactaceae), and although its true host remains unknown, the association with this host-complex is unique for the genus.

Dasymutilla nigra and D. imperialis, two new species of Dasymutilla Ashmead (Hymenoptera: Mutillidae), are described from males only from Texas and California, respectively. The males of both species have the integument and the pubescence entirely black, unlike any previously described species of Dasymutilla. They are easily distinguished from one another by the specific characters. Descriptions are given, including figures of the male genitalia.

The New World species of Irenangelus Schulz are revised, with a key to species, re-descriptions, distributional information and illustrations for each species. In addition, two new species, I. evansi and crossopus, are described from Costa Rica and Panama.

The Afrotropical species of the genus Jugurtia de Saussure, 1854 (Hymenoptera: Vespidae, Masarinae) are revised. Ten new species from southern Africa are described: damara (♀ and ♂), einensis (♀), elegans (♀), gariepensis (♀), hessei (♀), mandibulata (♀ and ♂), namibicola (♀ and ♂), nigrifrons (♀ and ♂), tibialis (♀ and ♂), zebra (♀). The female of nigrifrons is that previously attributed by Gess (1997) to duplicata Richards from which species it is now removed. Also described are the previously unknown males of alfkeni (du Buysson) and simpsoni Meade-Waldo. Full distributional data and distribution maps are given for all species except spinolae (de Saussure)—24 species in all, and forage plant records are included for 17 of these species. A key to species is given.

The eumenine genus Ancistroceroides is reported from the southwestern United States; the genus is otherwise neotropical. Two new species are described: Ancistroceroides evansi Carpenter from Texas and Mexico, and A. levis Carpenter from Arizona. Ancistroceroides cordovae Carpenter is proposed as a replacement name for A. conspicuus (de Saussure) non Smith. New combinations are: A. acuminatus (Brèthes), A. domingensis (Bequaert and Salt), A. erythraeus (Brèthes), A. fabienii (Brèthes), A. gribodoi (Zavattari), A. mearimensis (Zavattari), A. schulzi (Zavattari), A. sylveirae (de Saussure), and A. venustus (Brèthes). A new key to the genera of Eumeninae occurring in America North of Mexico is presented.

A cladistic analysis based on mitochondrial DNA and morphology of 40 species of Polistes is presented. Thirty-six New World species are treated with attention to classical taxonomic views, including subgeneric, species-group, and species membership. No previously proposed species groups are supported. Variants that have been sometimes thought conspecifics, including P. erythrocepahlus and P. infuscatus, are found to be more distinct than earlier taxonomy would suggest. Combination of morphology and molecules often provides stronger support for certain groupings, including a North American clade of the former Fuscopolistes. These results indicate that some morphological signal emerges only when the DNA and morphological data are analyzed together. Our results support the dissolution of all New World subgenera into a single subgenus, Aphanilopterus.

A new species of apoid wasp, Cerceris howardevansi, is described from Hispaniola, West Indies. It is the third species of the genus known from the Greater Antilles, and it belongs to the species group I of Scullen (1972).

Ammophila hevans Menke, new species, is described from Bolivia, Paraguay and Argentina. Taxonomic notes are provided for the following species of Ammophila: rufipes Guérin-Méneville, 1831; laeviceps Smith, 1873; ruficollis Reed, 1894; and ruficosta Spinola, 1851. New synonyms are: Ammophila variolosa Giner Marí, 1994 = rufipes Guérin-Méneville 1831; chilensis Reed, 1894 = laeviceps Smith, 1873. A lectotype is established for Ammophila chilensis Reed from Chile. The history of the acquisition of the Edwyn C. Reed collection in 1951 by the California Academy of Sciences is outlined.

Caupolicana floridana new species is a large bee from the southern part of the Florida peninsula, known from only two areas, Dade County where it may be extinct and Highland County. It is a close relative of C. electa (Cresson) which occurs in the southeastern states including northernmost Florida. Data on seasonal and floral behavior are included.

Caupolicana (Caupolicana) evansi, a new species similar to C. yarrowi (Cresson), is described from the Valley of Zapotitlán de las Salinas, in the Tehuacán Desert and from the nearby Cuicatlán Valley of Mexico. A key to the six North American species of Caupolicana s.str. is included.

Protandrena evansi Ruz and Chiappa n. sp. is described and illustrated. This new species was found at an aggregation of numerous individuals in a nesting site in Farellones, a locality of the Región Metropolitana in Central Chile, at 2612 m above sea level, visiting Senecio polygaloides Phil. (Asteraceae: Compositae), a plant endemic to the Andes. Some of its morphological features do not fit the diagnostic generic characters. Apical tergal hair bands have not been found before among the species of Protandrena s. l., including such subgenera as Metapsaenythia, Pterosarus, Heterosarus, Parasarus and Austropanurgus.

A new acantha species-group is erected in the genus Euhesma Michener. Three new species are described: E. acantha, E. loorea, and E. collaris. Scanning electron micrographs and line drawings illustrate the species-group and a key to females enables the separation of species. Known distributions are mapped.

The male and female of Chilicola (Chilicola) venticola, Packer, new species are described based upon material from Santa Cruz Province in Patagonian Argentina. The previously unknown females of C. (Chilioediscelis) araucana Toro and Moldenke and Chilimelissa australis Toro and Moldenke are also described. Notes on the nesting biology and adult behaviour of the species are given. Chilimelissa australis is the second xeromelissine known to nest in the ground and the possibility that other congeners nest in similar substrates is discussed. SEM analyses of brood cell lining materials are made for all three species and suggest the presence of some fibrous components, possibly silk, as in some other colletids. The ichneumonid Grotea sp. is recorded parasitizing brood cells of C. venticola.

The recent completion and publication of a revision of the Old World Fideliini (Megachilidae: Fideliinae) has provided new taxa and information for this little known tribe of bees. In this light, the data matrix for fideliine relationships is revised to include the newly described species as well as some corrections. Analysis of the data matrix for all fideliine species results in a single set of relationships, congruent with the previous hypothesis. An updated classification of the fideliines is provided, incorporating the new species. Fideliopsis is returned to generic rank, resulting in the following new combinations: Fideliopsis hessei (Whitehead and Eardley), F. fasciata (Whitehead and Eardley), and F. borearipa (Whitehead and Eardley). Keys are provided for the identification of all supraspecific taxa in Fideliini (with two new subtribes: Fideliina, new status, and Neofideliina, new subtribe) and a catalog of the species included. The expanded phylogeny and new floral information is used to provide a revised picture of fideliine-plant associations.