IO CHARLES T. BRUES. 



extend, and which they thrust through the surface of the water 

 for respiration. The mosquito larvae is by no means unique 

 among the lower Diptera in the general plan of its body although 

 it is the most highly specialized in several respects. 



A close morphological study of the larva? of a large number of 

 mosquitoes has brought to light many interesting facts. < )f 

 approximately 400 species known from North and Central 

 America, the larva? of a very large majority are known and have 

 been carefully examined. Comparative descriptions of a con- 

 siderable number of these were published in 1906 by Dyar and 

 Knab, and in their monograph on mosquitoes ('i2-'i7) Howard, 

 Dyar and Knab have included a complete account of all of the 

 known larva? from this region. In the earlier paper ('06) the 

 statement is made that "we are compelled to the conclusion that 

 specific limits are more sharply defined, or at least more readily 

 appreciable, in the larvae of Culicida?, than in the adults, although 

 generic limitations are less sharply drawn." There seems to be 

 no reason to change fundamentally this statement although it 

 appears from the later and more extensive publication that its 

 authors have been unable to find satisfactory diagnostic charac- 

 ters on the basis of larval structure for a small percentage of the 

 recognized species. Such characters as they do employ in their 

 keys_are readily perceived and the identification of larval mos- 

 quitoes is far easier than that of the adults, at least for those not 

 thoroughly familiar with the group. 



The two (or sometimes, three) subfamilies of the Culicida? as 

 at present constituted, are readily separable on the basis of 

 larval structure and the same is true of the two tribes of Culicina? 

 (true mosquitoes). So far as one may divest one's mind of 

 preconceived notions, it would appear that the genera of the 

 subfamilies would have been segregated in much the same manner 

 if the adults had remained unknown. It appears quite crrt.iin. 

 however, that the division of the tribes would have been different 

 to some extent, as the Anopheline mosquitoes present a striking 

 difference from the other members of the tribe in which they are 

 placed, on account of their extremely short breathing tube. 

 It must also be admitted tli.it in the adult condition they are a 

 very clearly characterized group. 



