BIOLOGY AND STRUCTURE OF HYDROPHILUS CARABOIDES 633 



dant des teguments d'une transparence parfaite ' (Portier, 

 1911, pp. 175-6). 



The inconvenience of the attitude during the feeding process 

 (Text-fig. 2) is increased for the larva of H. caraboides 

 by the necessity of breathing. For this purpose the larva bends 

 its body in such a way that the posterior end of the abdomen 



Text-fig. 3. 



Anterior margin of head and lower lip of newly-hatched larva. Base 

 of lower lip (lb) with simple lateral margins (m). On the sides 

 spined folds of the connective chitinous cuticula (t). ind, man- 

 dible ; Ig, ligula ; jM, palpi labiales. Zeiss, ob. AA, oc. 0. 



bearing the breathing aperture touches the surface of the 

 water (Brocher). 



In connexion with these peculiarities we shall look into some 

 of the details in the structure of the digestive apparatus of the 

 larva of H. caraboides. 



The wTll-developed and powerful mouth-parts of the larva 

 serve to seize the prey and to treat it mechanically. Having 

 seized some suitable animal, the larva of H. caraboides 

 pierces it with the teeth of its sickle-shaped mandibles (Text- 

 fig. 6, md), tearing open the integument of its prey. After 

 this the larva assumes the habitual feeding attitude and begins 

 to work energetically with all its mouth-parts, closing and 



