io8 



The Ohio Naturalist. 



[Vol.IV, No. 5, 



it must press against the femur of the middle legs and with them 

 doubtless forms a clasping organ ; the latter, upon the outer face 

 of the tibiae is adjusted to a special structure in the margin of the 

 abdomen and which serves to crowd the inner face of the tibia 

 against the abdominal wall. The claw is a broad, nail-like 

 structure apparently incapable of distinct flexion. Both tibia and 

 femur seem to provide special means of rigidly clasping the hairs 

 of the host animal, and if we bear in mind the subterranean habits 

 of its host, the development of such special organs may be 

 accounted for. 



Special organs for clasping occur also in the antennae and 

 abdominal brushes of certain species, but these have been men- 

 tioned, perhaps, in sufficient length in other papers. 



Lower fij^ures : Ilaeiiiatopinus urius. 



Upper left hand figure : H. macrocephalus. 



Upper right hand figure : Euhaematopinus abnorniis. 



