We compared the larval abundance of Mecistogaster modesta between bromeliads at ground level and canopy level in a primary tropical wet forest. Zygopteran abundance correlated strongly with bromeliad diameter at both levels. Although the per-bromeliad zygopteran abundance did not differ between vertical levels, M. modesta showed a strong vertical distribution in abundance owing to the…
A terminology is presented for structures and events in larval development of Odonata with the aim of bringing terms into conformity with those used for other insect orders in the light of accepted views of homology. The terms ‘exuvia’, ‘larva’, ‘prolarva’ and ‘stadium’ receive special mention. Records of the number of stadia required to complete…
Oviposition of Sympecma paedisca was observed in eastern Kazakstan. The main oviposition substrates were living Phragmites leaves. In comparison with European and Japanese populations we propose geographic variation in the proportional use of horizontal versus vertical oviposition substrates. Ovipositing females seemed to avoid the inner parts of Phragmites stands and there was a preference for…
A small inconspicuous spine, first detected at the base of the distal-most seta on each labial palpus of early stadia of two species of Enallagma, is reported to occur in final-stadium (F-0) larvae of Palaearctic and Nearctic E. cyathigerum, in F-0 of 31 other Nearctic species of Enallagma and in F-0 of three other coenagrionid…
Male aeshnid dragonflies at a small pond (circumference ca 90 m) in Cambridgeshire U.K. generally pursued males of other aeshnid species as well as their own. As a result of these encounters the pursued insect frequently left the pond, particularly when it belonged to a smaller species. Libellulids, which differed greatly from the aeshnids in…
Final-instar exuviae left at the emergence site by Odonata can provide information of high quality for measuring sex ratio, especially of Anisoptera. Criteria are listed according to which counts of such exuviae are acceptable for this purpose. Records of sex ratio of Odonata, published and unpublished, are critically reviewed, and 194 that meet the listed…
In the dragonfly Anax nigrofasciatus nigrofasciatus (Aeshnidae, Anisoptera), the X-tissue is the tissue which occupies the posterior corner of the larval eye and which forms the large facet region in the dorsal part of the adult compound eye after emergence. In the early period of the last larval instar, an ommatidial retinula of the X-tissue…