COLEOPTERA. 543 



at the roots of trees and grass ; a few live under the bark of 

 trees. 



The family GEORYSSID/E (Ge-o-rys'si-dae) includes only 

 two American species. " They are small, rounded, convex, 

 roughly sculptured, black insects, found at the margin of 

 streams, on wet sand ; they cover themselves with a mass of 

 mud, so that no part of the insect is visible." (LeConte and 

 Horn.) 



The family PARNlDyE (Par'ni-dae) includes small water 

 beetles, in which the legs are not fitted for swimming. The 

 tarsi are five-jointed ; the first four segments of the tarsi are 

 short and equal ; the fifth is longer than the others con- 

 joined ; the tarsal claws are unusually large. The body is 

 clothed with fine, silken hairs, which retain a film of air when 

 the insect is beneath the water. These beetles are found 

 adhering to stones or plants beneath the surface of the water. 

 The larva of Psephemis lecontei (Pse-phe'nus le-con'te-i) is 

 common in the East, clinging to the lower surface of stones 

 in rapid streams; and we have found it in muck near a 

 spring. It is very flat and circular in outline 

 (Fig. 652), and measures about five sixteenths 

 of an inch in length. It is rarely recognized 

 as an insect by the young collector. Other 

 larvae of this family have similar habits, and 

 resemble this species in form except that the 

 margin of the body is notched between the 

 segments. 



Fig. 652. 



The family HETEROCERID.E (Het-e-ro- 

 cer'i-dae) includes only the genus Heterocerus (Het-e-roc'e- 

 rus). These beetles " are oblong or subelongate, oval, 

 densely clothed with short silky pubescence, very finely 

 punctate, and of a brown color, with the elytra usually vari- 

 egated with undulated bands or spots of a yellow color. 

 They live in galleries which they excavate in sand or mud 

 at the margin of bodies of water, and, when disturbed, run 

 from their galleries and take flight." (LeConte and Horn.) 



