8o 



lateral sweeps, whereas Anopheline larvae exhibit 

 only irregular jerks. 



3. When kept in a vessel, Anopheline larvae 

 tend to collect round the edges with their heads 

 pointing towards the centre. In this position 

 the body of the larvae is often bent as it lies along 

 the curved surface of the capillarity film at the 

 edge. Cidex larvae and the larvae of M. turkhudj 

 frequently do not go to the side, but remain in 

 the more central portions of the fluid. 



4. Anopheline larvae, when full grown, possess 

 very small heads in proportion to the size of the 

 larvae (about eight mm. in length). In most of the 

 Culicidae the head is very large, with very pro- 

 minent and large antennae. 



5. Anopheline larvae have no 'spiracle tube,' 

 the tracheae open into a pit on the dorsum of the 

 eighth abdominal segment. In Stegomyia, the 

 spiracle tube is short and thick (Fig, 22), in 

 Taeniorhynchus (Fig. 22) very long and slender, 

 but in Anopheline larvae alone is this structure 

 absent (Fig. 21). 



Procure a considerable number of Anopheline 

 larvae, and ascertain the following points : — 



1 . The Moulting of A nophelines. — Note that as 

 Anopheline larvae grow in size they cast their skins. 

 Remove a cast skin by floating it upon a slide. 

 Note the perfect nature of the ' skin,' and how all 

 the chitinous structures are represented, even air 

 tubes. Dry the specimen upoii the slide and 

 mount in a drop of balsam. Observe how beauti- 

 fully certain hairs resembling fan -palm, leaves are 

 shewn (palmate hairs). {Vide p. 235). 



2. The Method of Feeding of Anophelines. — 

 Observe with a lens the action of the feeding 



