222 



or 2 such hairs ; frontal plates large ; maxillary palpi longer and much 

 stouter than antennae ; labial plate divided in center, the lateral pieces 

 digitate. Apical segment with 4 long processes which are furnished 

 with long fringes; pseudopods absent. 



This description applies to aquatic forms only; the terrestrial 

 forms are unknown to me. 



Pupa. — Palpi straight; antennae extending to or beyond bases of 

 wings. Thoracic respiratory organs long and slender, least chitinized 

 at apices; legs extending beyond apices of wings, disposed side by 

 side. Abdomen with a number of transverse setigerous ridges on 

 each dorsal and ventral segment, or with distinct tubercles in similar 

 series. 



HABITS OF LARVAE 



The only larvae known to me are aquatic. The very long fine 

 hairs on the apical abdominal segment take a very firm hold of the 

 surface of the water when the processes which they border are ex- 

 panded, and it requires considerable effort on the part of the larva to 

 detach them in order to descend. Hart has stated that detachment is 

 accomplished by throwing the cephalic extremity round in such a way 

 that the thoracic segments pass over the apex of the abdomen, and thus 

 their hold on the surface of the water is released. I have frequently 

 seen the larvae do this, but only in water too deep for them to get 

 hold of anything in the bottom. A considerable quantity of air is 

 carried down within the confines of the fringes of the apical processes 

 when the larva descends below the surface of the water, and when 

 this is exhausted the larva ascends for a fresh supply. In cases where 

 the specimens are able to feed without entirely submerging the body, 

 the apical segment is expanded on the surface of the water and forms 

 a conspicuous crater-like cavity within which are visible the eve-like 

 anal spiracles. 



The food consists of decaying vegetable matter and algae. 



I have found the larvae common at Muncie and White Heath. 111., 

 but only along the margins or in the muddy banks of streams. 



I have reared two species, but the larva of only one of them has 

 been associated with the pupa and imago. 



LiMNOPHiLA LUTEiPENXis Ostcn Sackeu 

 LimnopMla luteipennis Osten Sacken, Proc. Acad. Nat. Sci. Phila., 18.59, p. 236. 



The larva and pupa are described by Hart in the paper frequent- 

 ly cited herein*, and the following details should be accepted as sup- 

 plementary to that description. 



*Bu]l. Til. state Lab. Nat. Hist.. Vol. 4, Art. VI. pp. 202-204. 



