The South American genus Callyntra (Pimeliinae: Nycteliini) comprises 16 previously known species distributed in central Chile, plus a new species described from the central coastal mountain range: C. cantillana n.sp. A cladistic analysis of the 17 species of Callyntra is conducted. Callyntra comprises a natural group of species, characterized by nine synapomorphies from external morphology and internal skeletal anatomy. The species relationships are resolved. The paper includes scanning electron micrographs of the pronotum and clypeus of the new species. A discussion concerning the status of conservation of the five areas of endemism for Callyntra using the phylogenetic information is presented.

A revision is presented of the water treaders in the genus Mesovelia Mulsant & Rey occurring on New Guinea and nearby islands. A key to species is provided, followed by a taxonomic treatment and distribution of the species. The following new species are proposed: M. melanesica J. Polhemus & D. Polhemus from Papua New Guinea and Irian Jaya, and M. stysi J. Polhemus & D. Polhemus from southern Papua New Guinea. The following new synonymy is proposed: M. horvathi Lundblad 1933 = M. japonica Miyamoto 1964.

A new genus, Nexothrips, with two new species, N. delclaroi and N. perseae, is described from South America. The systematic position of this genus, and its relationships to the paleotropical Rhamphothrips genus-group, are discussed. A key is provided to the two new species, one of which was taken on Persea flowers in Colombia, the other from Hortia flowers in Brazil.

Two species of Lachesilla, in the group andra, collected in Central Mexico (Queretaro and Morelos-Oaxaca-Puebla, respectively), are here described and illustrated. The types are deposited in the National Insect Collection, Instituto de Biologia, UNAM, Mexico City.

Two species of Pseudacteon are described from parasitoids attacking fire ants, Solenopsis saevissima from Goiás and São Paulo states, Brazil. Pseudacteon disneyi new species, is closely related to P. arcuatus and P. pradei while P. fowleri new species, is a very singular species. A modification of Borgmeier's original species key is given for species identification, as well as for the insertion of P. lenkoi.

This paper records 75 species of plant bugs new to Canada, including the first report of Pinalitus cervinus (Herrich-Schaeffer) in North America. The following taxonomic changes are proposed: Melanotrichus vestitus (Uhler), lectotype designated and new combination; Macrotyloides symetricus Knight, new junior synonym of Macrotylus vestitus Uhler; and Paraproba nigrinervis Van Duzee, 1917, new junior synonym of Paraproba cincta Van Duzee, 1917.

The type series of eight species of Japanese Cercopoidea described by P. R. Uhler in the National Museum of Natural History, Washington D.C., were examined and lectotypes and paralectotypes are newly designated. Syntypes of four of these Uhler species found in the Natural History Museum, London, are also documented. Aphrophora impressa Metcalf & Horton is placed as a junior synonym of Aphrophora flavipes Uhler.

The literature on ant-like stone beetle–ant associations is reviewed and tabulated, bringing together nearly all published accounts of associations between these two groups. One hundred-seventeen species of Scydmaenidae (Coleoptera) in 20 genera are associated with 45 species of ants (Hymenoptera: Formicidae) in 28 genera. In addition, 16 species of Scydmaenidae are known associates of termites (Isoptera).

Aggregation behavior of Cordulecerus alopecinus Burmeisteir, a neotropical species of neuropteran from southeastern Brazil is described for the first time. Three roosts were studied during 14 days at the Reserva Florestal de Linhares, Espírito Santo state, Brazil. Males and females of each roost were marked on the first day of observation to evaluate possible flux of individuals among aggregations as well as roost fidelity. Roosts were censused daily at nightfall and at early morning, when notes on the behavior of aggregating individuals were also taken. Four tree species belonging to four families were used as roosting sites. The number of individuals in roosts varied daily, and roost size, as measured by the mean number of individuals, differed strikingly. A relatively low flux of individuals was detected among aggregations and most neuropterans usually returned to their original roost, showing some degree of roost fidelity. The sex ratio of aggregations was strongly biased to females and the observed number of dispersing individuals did not differ by sex. This new data suggests that aggregation behavior is a common feature within the genus Cordulecerus and that aggregations can be more than a random and casual assemblage of individuals, deserving futher quantitative investigations.

The intrinsic rate of increase of a population in terms of fecundity, developmental time, and longevity, is known to affect the colonizing ability of species. We present evidence that Polistes dominulus, an invasive European paper wasp introduced to the United States, exhibits life-history traits that predispose it to successful colonization. This predisposition is not simply due to the more frequent pleometrosis of P. dominulus. Many authors have speculated, based on cursory observations, that P. dominulus is replacing native species including P. metricus. The possibility of replacement in light of the data is discussed.

Peristenus digoneutis was discovered in one new state (Maine) and in 15 new counties in Maine, New Hampshire, New York, Pennsylvania, and Vermont during 1997–1999. These new records increased the number of counties where this parasite has been found by 42%, to a total of 51 counties in eight states. No permanent establishments of P. digoneutis have been found south of New York City, which suggests that high summer temperatures are limiting its spread southward. A good agreement was found between the parasite's southernmost establishment locations and a maximum summer temperature/duration of 30°C (86°F) for 14 to 30 days. This temperature limit suggests that P. digoneutis can disperse westward both north and south of Lake Erie, across southern Ontario and northern Ohio, to Michigan and Wisconsin. Establishment south of New York City (latitude 40.5°N) is unlikely, except possibly along the higher/cooler elevations of the Appalachian Mountains.

To analyze morphological caste differentiation in social wasps, variable reduction methods, such as the comparisons of Mahalanobis distances and the scatter diagrams of canonical scores and the analysis of mean queen/worker ratio of each morphometric characters, could only show whether there are some differences between the castes or not. These methods, on the other hand, do not document major aspects of the nature of morphological caste differentiation; that is, whether morphological differentiations are allometric or non-size based is not shown.

Male aristae of laboratory reared Ceratitis capitata were longer, both in absolute terms and in proportion to body size, than those of females. Both male and female aristae had microtrichia which lacked membranes at the base, but female aristae had more microtrichia that were more evenly distributed than those of males. Female aristae also had more curves in the distal end. Experimental removal of female aristae resulted in less frequent mounting, and less copulation once mounting had occurred than in control females. Stimuli sensed by the female's arista may thus affect her readiness to copulate.