Rehn's (1955) two subgenera Microtylopteryx (Microtylopteryx) and Microtylopteryx (Tristanacris), each comprising several species and subspecies, are here each considered to represent a single species, M. hebardi Rehn 1905 and M. fusiformis Rehn 1905 respectively. I arrive at this conclusion on the basis of a) the genital anatomy, and b) morphometric analysis of all the previously named taxa and several previously unsampled populations. There are no differences within each of these taxa in internal or external genital structure. In the morphometric analysis, measures specifically designed to correspond to Rehn's diagnoses were used, and new material was collected from the various type localities to supplement the original material. The results show that the original diagnoses, which were based on small samples, do not adequately represent the populations from which the type series were drawn.

Virtually every geographically circumscribed population which has been investigated differs from the rest, often significantly, in the average of one or more quantitative characters. However, the degree of overlap between the different populations in the range of these characters is typically very large, and often complete, and individual specimens therefore cannot be allocated reliably to particular populations on the basis of their morphology. All such overlapping populations are here considered to belong to a single taxon. Where, exceptionally, there is no overlap between populations in some character, and individuals can be reliably allocated to a specific population on its basis, subspecific ranks have been allocated.

Within Microtylopteryx (Microtylopteryx), M. hebardi caligo Rehn is synonymized with M. hebardi Rehn, and M. nigrigena Hebard is relegated to subspecific rank as M. hebardi nigrigena. Within M. (Tristanacris) two species (talamancae Rehn, tristani Rehn) and one subspecies (fusiformis lamprus Rehn) are synonomized with M. fusiformis Rehn. M. worthi Rehn and M. chiapensis Rehn are relegated to subspecific rank within M. fusiformis, and one further new subspecies (M. f. fastigiata n. ssp) from Western Panama is erected. Each of Rehn's subgenera thus becomes monospecific, and it is suggested that the division into two subgenera is now redundant.

A key to species and subspecies is given, and distribution maps.

Six specimens collected in the Admiralty Islands have been examined and are described as 2 new species. Four of these are named Megacrania vickeri. The other 2 specimens are described as M. Artus. They are compared with the most closely related species of Megacrania.

Seventeen new species of the predaceous katydid genus Phlugis Karny (Meconematinae) are described and figured. All of these species were collected from rainforests in northern Peru. Three of them — along with the already described species, P. teres (DeGeer) — regularly were captured along trails at ground level; the remaining 14 were collected from treetop canopies 10 to 30 m above ground level, using pesticide fogging methods. Based on the numbers of new forms collected from tree canopies, it is probable that many species of this already large genus are yet to be discovered as this niche is explored more thoroughly.

In the perspective of the general review of the ‘archaeorthopterid’ insects (including Orthoptera and the extinct orders Caloneurodea and Titanoptera), a redescription of Protophasma dumasii Brongniart 1879, type species of the Protophasmatidae Brongniart 1885, is provided. The forewing morphology allows the assignment of this taxon to the Archaeorthoptera, but the hindwing morphology is very similar to that of Blattodea, with some particular features. Protophasma dumasii shares several symplesiomorphies with the Blattodea and Neoptera. Thus, this species is a good candidate to be the absolute out-group for the future phylogenetic analysis of the Archaeorthoptera.

During the locust control operation held in South Morocco in 1995, a quantitative study was carried out on morphologic measures of 586 adults of both sexes of the desert locust Schistocerca gregaria. The results of the study reveal that these populations present a mosaïc structure with the predominance of the gregarious phase at the beginning of the outbreak in the localities of Foum-Bousseroual and M'Rikha in the south east of Errachidia (Z₁). The gregarisation degree diminishes in the regions situated to the north of this zone (Z₁). The gregarious phase prevalence in the south (of Z₁) may be related to favorable conditions which have contributed to maintaining the allochthonous gregarious populations.

The solitary populations localised in the north of this zone and in the Tata zone (Z₂) are indigenous. The bad environmental conditions combined with timely control operations stopped the departure of a new invasion.

The effect of an extract of Peganum harmala seeds was studied on the 5th larval instar and on the ovarian growth of desert locusts under laboratory conditions. The results obtained show, in the 5th larval instar, an 8–d delay of imaginal moulting, and a mortality rate of 100%, reached on the 16^th day after the beginning of the treatment.

In females treated at the adult instar, 62.5% among them had their ovarian development blocked. Those surviving showed an 8–d delay of egg–laying and a decrease in hatching rate.

We have noted, in the treated insects, a decrease in physical activity (immobility, trembling of appendages), a decrease in weight, and a loss of water in the form of wet faeces.

Concurrently, a phytochemical study conducted on the same ethanolic extract has shown the presence of a majority of the indolic alkaloids responsible for the toxicity of the plant.

A new katydid from the tropical rainforests of northern Australia, Leucopodoptera eumundii gen. et sp. nov., is described. Morphological examination, scanning electron microscopy imaging and cytological preparations were used to establish defining characteristics. Principal taxonomic characters include the stridulatory file of the male and the ovipositor of the female. Laboratory and field-based observations give insight into the distribution, ecology and life-history of the species.

The entomopathogenic fungus Metarhizium anisopliae var. acridum Metsch. Sor. (Deuteromycotina: Hyphomycetes), was tested under laboratory and field conditions against the Central American locust Schistocerca piceifrons Walker (Orthoptera: Acrididae). Adults of S. piceifrons treated under laboratory conditions with the isolate MaPL40, 1.5 × 10³ conidia/insect, showed 97% mortality 12 d after inoculation with a conidia mineral oil formulation and 59% mortality within the same period, when treated with a conidia-water suspension. Field trials against bands of S. piceifrons were undertaken with the isolates MaPL32 and MaPl40. Formulations of both isolates were applied as ULV at a dose of 50g conidia (2.5 × 10¹²)/litre citrolina oil/ha. Bands were followed for 13 d after treatment in treated and untreated blocks, to assess decline every other day. Bands that remained in the treated area for the full period showed 99% decline when treated with the MaPL32 isolate, while those treated with the MaPL40 isolate declined 85% within the same period. Bands that left the treated area a few days after treatment declined 94% by day 13 when treated with the MaPL32 isolate, and 84% when treated with the isolate MaPL40. Results suggest that M. anisopliae var. acridum may substantially reduce nymphal populations of S. piceifrons under field conditions, though further studies are necessary for the operational use of M. anisoplie var. acridum as part of a locust integrated management program in Mexico.