Odonatological Abstracts

(289) CHAISEMARTIN, C. & L. MOUZAT, 1971. Variations ecophenotypiques de Thomeostasie chez les insectes; ampleur des mecanismes regulateurs chez quelques formes dulgaquicoles. C.R. Seances Soc. Biol. Fil. 165; 2167-2171. – (Lab. Biol, anim., UER Sci. Exactes et Nat., Limoges, France). The range of regulatory mechanisms of ecophenotypic variation in homeostasis was studied in several freshwater insect orders (Trichoptera, Megaloptera, Heteroptera, Coleoptera), including the representatives of odon. genera Libellula and Sympetrum. Determination of K"*~, Ca“"*", Mg2"*", Cl , HCO3 > and proteins in the haemolymph were made. The phylogenetically least advanced groups had a high level of Na"*” and Cl" in the blood. The restoration of haemolymph ionic balance following haemorrhage was studied in L. depressa and in Agabus sp. (Col.) at 4°C over a 10-day period. Evidence was found for rapid Na"t mobilisation and a slower replacement of K+. The levels of Ca2+ and Mg2+ were relatively stable. Homeostasis appeared to be best regulated in the spp. inhabiting stagnant water, Sympetrum sp. and Sialis sp. (Megal.). (290) DEJOUX, C„ L. LAUZANNE & C. LEVEQUE, 1971. Prospection hydrobiologique du Lac de Lere (Tchad) et des mares avoisinantes. IV. Faune benthique. Cah. ORSTOM, ser. Hydrobiol. 5 (2): 179-188. – (Centre ORSTOM, B.P. 65. Fort-Lamy, Repub. Chad). During a hydrobiological exploration of the Lac de Lere and neighbouring pools, Republic of Chad, Africa, no Odon. were found in bottom samples of the lake, but from the pools round the edge of it 4 spp. were recovered, viz. Pseudagrion nubicum, Lestes sp., Macromia nyanzana and Diplacodes lefebvrei. For the list of the odon. fauna of Chad reference is made to C. Dejoux, 1968, Contribution a 1’etude des insectes aquatiques du Tchad. Catalogue des Chironomidae, Chaoboridae, Odonates, Trichopteres, Hemipteres, Ephemeropteres, Cah. ORSTOM, ser. Hydrobiol. 2 (2): 52-78.