22 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 39 



Larval feeding. — The process of feeding by nonpredaceous larvae 

 is not a mere matter of having food particles washed into the mouth 

 by streams of water from the vibrating labral brushes. It involves 

 cooperative action on the part of the labrum, the epipharyngeal 

 apparatus, the mandibles, the maxillae, the labiohypopharynx, and the 

 pharynx. The whole feeding process has been minutely described by 

 Schremmer (1949) for the Anopheles larva, in which it is more readily 



%': 



. 



A 



m 



B :: --fi;§P^ 



CWoe 



Fig. 8. — The larval epipharyngeal apparatus and the pharynx. 



A, Aedes^ aegypti, epipharyngeal apparatus. B, Culcx sp., same. C, Anopheles 

 maciilipennis, pharynx and its muscles, dorsal (from Schremmer, 1949). D, 

 Same, filter-bearing rib of pharynx. E, Same, cross section of pharynx (from 

 Imms, 1907). 



cmcl, circular muscle ; fb, filter brush ; Mth, mouth ; Oe, oesophagus ; Phy, 

 pharynx; tmcl, transverse muscles. 



observed than in other species because the head is held with its under- 

 side turned upward against the surface of the water. Briefly, Schrem- 

 mer's account is as follows. 



The movements of the lateral brushes of the labrum create currents 

 in the water that converge to the front of the head and are directed 

 medially by the middle brush. With the backward stroke of the lateral 

 brushes the mandibles and the maxillae are closed upon them, and 

 as the brushes again go forward particles that may be adhering to 



