135 



Feytaud (J. ) & Gendre (E. ). Sur la Resistance des Larves de Culicides 

 dans les Eaux picriqu6es. — Bull. Soc. Path. ExoL, Paris, xii, no. 5, 

 14th Ma)^ 1919, pp. 231-234. 



One of the authors, visiting a melinite factory in July 1918, was 

 surprised to find Anophelines breeding in water heavily tainted with 

 sludge from the factory. The brown tinge of the water made it appear 

 unlikely to harbour any fauna, while it had befen considered certain 

 that the presence of the sediment in the water would prevent 

 Anophelines from breeding and would be, in fact, a guarantee against 

 any possibility of the presence of malaria. Having discovered the 

 possibilitv of breeding in such media, experiments were undertaken to 

 determine the resistance of the larvae in solutions of picric acid at 

 various degrees of concentration, and to work out a suitable treatment 

 for the reservoirs in mehnite factories. A solution of 1 part picric 

 acid in 80 parts water was chosen and this was used in varying dilutions 

 on larvae of Anopheles bifurcatus, A. maculipennis, Culex pipiens 

 and Theobaldia (C.) annidata. A. maculipennis can withstand a 

 stronger solution than A. bifurcatus, the lan^ae apparently being 

 scarcely inconvenienced by dilutions stronger than 1/500. The larvae 

 of Culex are more resistant and lived for several days in a dilution of 

 1/50. It is quite probable that the resistance is greater when the 

 larvae, instead of being plunged suddenly into a picric solution, 

 develop in this medium from their birth, and they can certainly 

 stand a greater strength when it is added gradually. It was noticed 

 that all the larvae of A. macvUpennis recovered from the tainted water 

 of the factory were small in size, indicating perhaps that the majority 

 of them die before reaching maturity, or it may be that metamorphosis 

 is accelerated owing to the unfavourable medium. It is possible 

 that in time a dwarf race might develop which would be still more 

 resistant. As regards the poisonous effect of picric acid alone, without 

 reckoning any other substance present in the sediment, it is necessary 

 to use at least one part of pure picric acid to 8,000 parts of water. 



ScHWETz (J.). L'Identit6 des Conditions geo-botaniques des Cites k 

 Pupes de la 67. palpalis, de la Gl. fusca, de la Gl. brevipalpis, de la 

 Gl. pallidipes, et de la Gl. morsitans. — Bull. Soc. Path. Exot., Paris, 

 xii, no. 5, 14th May 1919, pp. 234-238. 



While some records have been published of the haunts of the pupae 

 of Glossina palpalis and of G. morsitans, very little seems to be known 

 about the favourite breeding-places of G. brevipalpis, G. pallidipes 

 and G. fusca. The author has been studying these five species during 

 1916-1918 in the north of the province of Katanga (Belgian Congo), 

 and gives a preliminary resume of his observations. Pupae of two 

 and even three species have been found together, indicating that 

 identical or verv similar spots are chosen for the deposition of larvae. 

 The absolutely essential conditions for pupae of all species of Glossina 

 are (1) dry, loose soil, and (2) shade. Local conditions force the flies 

 to a certain adaptation, and thus a difference appears to exist at first 

 glance between the breeding-places of various species. But this 

 apparent difference is due only to the fact that the various species 

 choose their habitat with a view to the special vegetation necessary 

 to them. G. palpalis breeds on the wooded banks of waterways' 



