RECENT ADVANCES IN SCIENCE 415 



inhabiting the soil throws considerable light on the habits of 

 ground-feeding birds and a comparison of the fauna of two 

 areas differing in soil and vegetation helps to solve the question 

 as to the amount these differences can be explained by varying 

 edaphic factors. The criterion of the true surroundings of an 

 insect is taken to be the place in which it breeds. 



" The Relation between the Hatching of the Eggs and the 

 Development of the Larva of Stegomyia fasciata (Aedes calopus) 

 and the Presence of Bacteria and Yeasts " has been fully 

 investigated by Atkin and Bacot (Parasit. July 17). It is 

 found that moulds are of no use to the developing larva, and 

 indeed detrimental, probably owing to the fact that they utilise 

 the available food if not actively harmful. The larvae on the 

 other hand feed on bacteria and yeasts, which form a sufficient 

 diet even in the absence of other foods. They grow very poorly 

 in the absence of such organisms, and it is practically impossible 

 to bring them to the adult stage in sterile solutions. This 

 information may be of service in keeping down this species of 

 mosquito, and conversely it is certainly useful to the Sanitary 

 Inspector who wishes to hatch out his flies, and failure to do this 

 in the past has probably resulted from the water being deficient 

 in bacteria. Other papers include : " The Chromosome Com- 

 plex of Culex pipiens, Part II. Fertilisation," by Taylor {Quart. 

 Jour. Micro. Set. vol. lxii. August 17), and " Notes on Nycteri- 

 biidae, with Descriptions of Two New Genera," by Scott (Para- 

 sit. July 17). The last gives an account of these bizarre 

 and extremely highly modified Diptera which are only found 

 parasitic on Bats. It not merely gives a description of the new 

 genera, but also a very useful summary of the biology of these 

 strange creatures, their habits, their reproduction and general 

 life-history. 



Other papers include : "A Revision of the Wasps of the 

 Genus Tachytes inhabiting the Ethiopian Region " (Ann. and 

 Mag. Nat. Hist. July 17) and " Notes on the Braconidce in the 

 British Museum" (ibid. September 17), both by Turner; " De- 

 scriptions and Records of Bees," by Cockerell (ibid. September 

 17); " Notes on the Hymenopterous Families Bathylidce and 

 Rhopalosomidce ," by Turner and Waterston (ibid. July 17) ; and 

 " New Records of Natal Bees," by Cockerell (ibid. Septem- 

 ber 17). 



" The Cytoplasmic Inclusions of the Germ-cells," by 



