Stages of Metamorphosis : the Egg 



6. Palpi very short in both sexes ... ... Aedeomyina. 



1. Proboscis short and not formed for piercing .. Corethrina. 



Many of these sub-families are of importance to the worker on 

 tropical diseases only in so far that some knowledge of their 

 characteristics is essential to enable him to distinguish them from 

 the mosquitoes which he especially desires to study. The Megar- 

 hinincB are rare and cannot easily be confused with any other mem- 

 bers of the Culicidce on account of their large size, brilliant colour, 

 and long curved proboscis. The greater number of species have 

 also a curious caudal tuft of brilliantly coloured hair-like scales at 

 the end of the abdomen on each side. The Aedeomyince and Core- 

 thrince are at present of no importance from a pathological point 

 of view ; the former are easily recognised by their very short palpi 

 in both sexes, and the latter by their very short non-piercing pro- 

 boscis which somewhat resembles that of the Tabanidce or gad- 



o 



flies. The Heptaphlebomyince and JoUotince may, for all practical 

 purposes, be considered as belonging to the Culicinae. Each of 

 these sub-families contains but one species, which, in the case of 

 Heptaphlebomyina, was placed in a distinct sub-family because it 

 had seven longitudinal wing veins instead of six, and in the case 

 of Joblotina because the metanotum carried hairs and scales. 



By far the most important of the sub-families are the Ano- 

 phelina and the Culicina, which contain all the species of mosqui- 

 toes known to be connected with the transmission of disease. In 

 the former sub-family are included all the mosquitoes usually known 

 as "anopheles," and in the latter most of those usually known as 

 " culex." In fact, for the student of tropical medicine, no very ela- 

 borate classification of the family Culicidce is necessary or advisable, 

 and a knowledge of the differences between the two groups " Culex" 

 and " Anopheles," together with a knowledge of the more important 

 characteristics of a few of the genera included in the sub-family 

 Oulicina are all that are essential before the task of the identifi- 

 cation of individual species is commenced. These points will be 

 referred to in the following more detailed account of the different 

 stages in the metamorphosis of mosquitoes. 



THE EGG OR OVUM 



The eggs of most "culex" mosquitoes, before being deposited by 

 the female, are collected together, in the angle made by the crossing 



61 



