75 



This appearance is diagnostic of the Anopheline 

 larva. One species (M. turkhudi) does not, however, 

 rest in this position, but after rising to the surface in 

 a horizontal position slowly sinks until the tail only 

 touches the surface. 



Anopheline larvae, which are about to turn into 

 nymphae, also sometimes tend to sink, so that the 

 head is directed obliquely downwards (often seen in 

 M. rossi). 



One species at least of Culex (C. concolor) adopts 

 a nearly horizontal attitude. The line of indentations 

 of the surface film mentioned above, is not however 

 seen. 



2. When disturbed, Anopheline larvae dart into 

 the water, or what is very characteristic, if not greatly 

 disturbed, they pass by a series of wriggling jerks along 

 the surface of the water. 



When moving up towards the surface, an 

 Anopheline moves in a much more irregular and jerky 

 manner than a Culicine larva. 



3. 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 Culicinae 

 the head is very large, with very prominent and large 

 antennae. 



4. Ano-pheline larvae have no syphon, the tracheae 

 opening into a pit on the dorsum of the eighth 

 abdominal segment. 



Procure a considerable number of Anopheline 

 larvae, and ascertain the following points : 



I. The Moulting of Anophelines. 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. 



