12 Mosquitoes 



and a rosette of the latter is on the larger end. One 

 may often, under the most favourable of conditions, 

 work for hours before the pattern can be determined. 

 The membrane is commonly supposed to be filled 

 with air, but I rather suspect that it contains gelatin, 

 that it is a relic of the highly developed gelatinous 

 envelope found among the eggs of many of the other 

 gnats, notably the Chironomidae. In fact, if it were 

 air, it is scarcely probable that the single eggs would 

 sink as easily as they do. The Anopheles eggs, 

 which are single and float, have considerably more 

 of the membrane proportionately, and those Chiron- 

 omid egg masses which are surrounded with large 

 masses of gelatin do not easily sink. 



This seems also to be the view of Dr. Goeldi, who, 

 in his splendid work, Os Mosquitos no Para, speaks 

 of the minute globule at the pointed end of the egg 

 of C. fatigans (a raft layer) as containing a gelatin- 

 ous or mucilaginous substance, and of the base being 

 also covered by a layer of this. He thinks that the 

 gelatine both serves as a float and, possibly, as the 

 first meal of the newly hatched larvae. 



Larv£e. — The larva, or "wiggler," consists of head, 

 thorax, and nine abdominal segments, with their ap- 

 pendages (Plate III, opp. page 16). The head is flat- 

 tened, usually wider than the joints of the abdomen, 

 and covered with heavy chitin, varying from black to 

 light yellow in colour, sometimes more or less spotted. 

 At the sides are the eyes, which seem to be trans- 

 itional between the simple and the compound eyes. 

 They are black, and generally of a crescentic form. 

 They alter somewhat during the different moults. In 



