Larvae and Pupae 69 



them will eat their cast skins, as will also all of those 

 outside of this class. Between the two groups 

 are two others, somewhat intermediate — viz., the 

 Uranoteenia and the AnopJiclcs groups. That the 

 differences in habits are correlated with marked dif- 

 ferences in the structure of the mouth-parts will be 

 seen by the following comparison. 1 



In the insectivorous group the mouth-parts are 

 eminently fitted to the diet. The " brushes " are 

 here a few stiff grappling hooks ; the mandibles 

 possess long, heavy, curved spines for seizing, and 

 great pointed teeth for tearing (Fig. 14, a, page 73) ; 

 the maxillae: are squared, heavy, and fitted with 

 many stiff, usually curved spines, evidently adapted 

 for retaining a struggling victim (Fig. 13, c, page 68). 



In the non-insectivores, whose food is usually 

 microscopic, the "brushes" are often of marvel- 

 lously delicate hairs, very numerous and fitted to 

 form a current which will draw small particles into 

 the mouth. The hairs and spines on the mandibles 

 are movable and not so heavy as in the former 

 group ; they are evidently sieves or tactile, or are 

 used to comb off the brushes, which are frequently 

 drawn through them (Fig. 14, d, page 73). The 

 biting part is small, with rather blunt, crushing teeth. 

 The maxillae are conical, with long brushes atop, to 

 thrust food down the gullet, and fine hair sieves on 

 their sides (Fig. 13, a, e, page 68). 



Anopheles and Uranotcenia seem to correspond 



» For more detailed comparison in tabulated form see the author's 

 article, " Mouth-Parts of Mosquito Larvce as Indicative of Habits," 

 Psyclie, Feb., 1906, pp. 1 1 to 21. 



