22 Bulletin American Museum of Natural History [Vol. XLII 



Single eggs were deposited on the stones or algae in an aquarium, 

 out of water but in moist places. They were either entirely naked or, at 

 times, covered rather uniformly with loosely applied silk. The silk 

 was more compact, however, than in the scattered silk of the Cym- 

 biodyta egg-masses but not as closely applied as in the complete egg-cases. 

 The eggs were most frequent during May but some were laid the first 

 part of July. From seven to ten days were required for incubation. 



The larvae are very different from those of the Hydrobiinse and even 

 from those of the Helophorinae but are closely allied to the Limnebiin*. 

 On land, they move very rapidly and almost seem to run. They are 

 very clumsy in water and doubtless spend their life on land but in moist 

 situations. According to d'Orchymont, p. 190, the life of the larva 

 probably lasts only two or three months. Adults of 0. impressus, 

 which he captured the first of August in order to restock his aquaria, 

 were not fully colored, thereby indicating their recent emergence. 



Ochthebius tuberculatus LeConte (foveicollis LeConte) 



Plate III 



At times the collecting of this species proved so easy that they 

 could be picked up almost indefinitely, the collector stopping only to 

 wash them out. In the middle of September 1916 many were found in 

 gravelly places which were practically devoid of vegetation. One can 

 easily recognize them in the water because of their somewhat heart- 

 shaped abdomen, which often sinks lower than the rest of the body. 



Egg. — Length, 0.538 mm.; width, 0.215 mm. Naked or covered with 

 loosely applied silk which is placed regularly so that the whole is uniform in shape. 



Newly Hatched Larva. — Length, 1.345 mm.; width, 0.242 mm. Whitish, 

 except the. chitinized portions which soon become brown. Integument with many 

 inconspicuous setulse as well as regularly arranged setse, which are fairly long, rigid, 

 and brownish. 



Head well rounded, globular; fronto-clypeal suture fairly well indicated; frontal 

 sutures converging, uniting behind the middle of the head to form the epicranial 

 suture, the whole presenting a Y-shaped appearance; frons somewhat triangular. 



Gula fairly small,, constricted laterally, the anterior and posterior angles produced 

 into arms; cervical sclent es, if present, not noticeable. Epistoma apparently marked 

 off from the frons by an irregular group of minute tubercles. 



Clypeus fairly distinct, transverse, slightly arched, wider than the labrum and 

 with a transverse row of six setae, the median two widely separated but the others 

 equidistant, near the anterior margin 



Labrum somewhat semicircular with four lateral seta? on each side, the anterior 

 one ' bifurcate, short, and blunt; a stout seta in front of the latter; two, small, 

 adjacent tubercles just inside the anterior margin and two others in a horizontal row 



