REPORT OF THE STATE ENTOMOLOGIST I904 445 



from the thornlike tip is seen in those with scales tipped with a 

 nearly uniform series of ciliate or setaceous processes. The comb 

 of Psorophora is exceedingly ■ peculiar in that the posterior margin 

 of stout, trispinose scales partially incloses an area thickly clothed 

 with much finer scales, each with its posterior margin finely serrate 

 like the teeth of a comb. There are considerable variations in the 

 number of scales on certain species, and in most forms having a large 

 number of scales in the comb, there is frequently a great difference in 

 structure between the component scales, the greatest divergence 

 from the type form being observed at the dorsal or ventral angles 

 of the patch. The Anopheline larvae are remarkable because of the 

 highly specialized comb. It is subdorsal and consists of a basal 

 plate bearing a series of posterior, sometimes pectinate teeth, a 

 structure widely different from that presented by other Culicidae. 



The degree of chitinization of the anal or ninth segment is 

 frequently of considerable value in identifying species and there is 

 considerable variation in the ventral tuft. This is greatly developed 

 in certain forms and almost rudimentary in others. A most inter- 

 esting structure occurs on this segment in Megarhinus larvae; 

 namely, a rudimentary spiracle indicating plainly a -former ter- 

 restrial habit. Corethrinae larvae have this segment very weakly 

 chitinized and the larvae of Sayomyia may at once be recognized 

 by the peculiar ventral hooks attached to the posterior extremity. 



Key for the identification of mosquito larvae 



Identification of mosquito larvae is of importance in all work 

 designed to control these species, and this is particularly true of 

 localities where prevention of disease is the main object. This 

 being the case, we have taken the opportunity of revising and 

 extending our recently prepared table for the separation of larvae, 

 in the hope that it will prove of service to those engaged in control 

 work of one kind or another. 

 a Air tube long, at least four times as long as the diameter of its base 



b Air tube very long, slender, slightly constricted in the middle ; antennae 



white banded Little black mosquito ,Culex territans 



hh Air tube very long, stout, tapering uniformly 



c Comb scales 60, pecten teeth three to four branched 



Unhanded marsh mosquito, Culex salinarius 



cc Comb scales about 80, pecten apparently simple 



Culicella dyari 

 ccc Comb scales narrow, spinelike, about 20 in a row, resembling a 



grating Culicella melanurus 



bbb Air tube about five times the width of its base 



c Pecten pale, divided into three to five long, slander processes 



