352 THE CANADIAN ENTOMOLOGIST. 



these larvre which live mostly at the water-surface. Air vesicles of this 

 character occur in various degrees of development in Culiciiie larvae. In 

 the larvse of Ma?isonia signifer and M. fascipes they represent a condition 

 very similar to that in Corethra. 



Miss Mitchell objects to the placing o{ Dixa with the Culicidaj, and 

 one of her reasons is that " the antennse of the adults are almost bare, and 

 are quite similar in the two sexes." In another place I have already 

 shown that Miss Mitchell's startlingly simple classification of the Culicidse 

 according to antennal characters* resulted from her ignorance of the facts. ^ 

 It may be further pointed out that in the Ciiironomidce the same condi- 

 tions are found. In most of the genera the male antennae are plumose, 

 but in a few they are similar to those of the female. It does not appear 

 that these conditions have anything to do with the grouping of the genera. 

 The larval characters of Dixa enumerated by Miss Mitchell as of family 

 value, cannot be conceded such importance. The segmentation of the 

 thorax is fairly distinct in the Culicid larva?. As to the prolegs, although 

 I have no material at hand, I am strongly under the impression that their 

 number differs in the different species, if, indeed, they may not be absent 

 altogether. Miss Mitchell indicates them on the first and second 

 abdominal segments. Meinert's figure of the larva of Dixa shows them 

 on the fifth, sixth and seventh segments as well." The characteristic 

 ])roleg on the first thoracic segment of most Chironomidse is familiar to all 

 students. It is present in most genera of Chironomida^, but there are 

 some in which it is wholly absent. Are these to be excluded from the 

 family ? Moreover, a series of prolegs, similar to ihose of Z)/.^-(^, occurs in 

 the larva of the Chironomid Psamathioiiiyia. Miss Mitchell describes 

 the pupa Dixa as " inactive, iloaling quietly on the surface," the implica- 

 tion being that they differ markedly from the Culicidie. In a species which 

 the writer bred the pup?e were just as "inactive" as those of Culicids, and, 

 like them, when disturbed made rapidly for the bottom. In another 

 species which the writer bred the larva leaves the water to pupate, and the 

 pupa remains attached to a blade of grass and motionless, some distance 

 above the water surface. 



4. E. G. Mitchell : X'alidity of the Culicid .subfamily Deinoceritinae. Psyche, 

 XIV, I 1-13, 1907. 



5. F". Knab : Deinocerites again. Journ. N. Y. Enl. Soc, XV, 121-123, 

 1907. 



6. Fr. Meinert : De encephale Mygg-elarver, pi. 1\', iSSb. 



