<J2 GNATS Oil MOSQUITOES — CHAPTER IV 



character, and from their outer posterior corner there 

 springs the maxillary palp, which is larger and more 

 acutely conical, and also carries certain specialised bristles. 

 Proportionately to the head the thorax is a good deal 

 larger, and exhibits three rows of bristles besides the large 

 lateral tufts, the posterior of which are the largest in the 

 body, while those of the pro- and mesothorax are of 

 insignificant size. The abdomen is cylindrical, and is 

 very distinctly separated into nine segments, which increase 

 in length while they diminish in breadth from before back. 

 The lateral tufts of bristles of the three anterior segments 

 are exceptionally large, but the hinder ones are very small. 



On the dorsal surface of the eighth segment are a pair of 

 simply-formed spiracles, which can be withdrawn beneath 

 a fold of skin when the insect requires to protect their 

 openings. At the same time, if examined in profile, it is 

 evident that the difference between tlie larvae of Cidex and 

 Anopheles is really one of degree rather than of kind, and 

 that although rudimentary in the latter, all the parts of 

 the long syphon of Culex are really present, and are 

 especially evident in some species ; while, on the other 

 hand, as already remarked, in some Cidlccs the syphon is 

 very short. The last segment carries the four anal tubercles, 

 which, as well as the tail-fans, are rather less developed 

 than in Culex. Although arranged on the same general 

 plan within the body, the tracheal system is much less 

 developed, the main longitudinal trunks being of very 

 ordinary size, and quite without hydrostatic dilatations 

 in any part of their course. 



The pupa differs from that of Culex cmly in the respira- 

 tory trumpets being shorter and more squarely cut at 

 the end. It may be distinguished from the pupa of Mo- 

 clilonyx by the fact that the eighth instead of the seventh 

 abdominal segment is disproportionately long. In the 

 particular species examined by Meinert the pupa, like the 

 larva, is grass-green, but this coloration is not universal 

 in the genus, and those of Indian species, like the larva?, 

 are brown. Working in Italy on the same species, Grassi 

 was unable to confirm Meinert's statement as to a green 

 coloration, finding the larva, as we do in India, brown. As 



