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 rigidl}- 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 figures ; Ilaeiuatopinus urius. 
Upper left hand figure ; H. inacrocephalus. 
Upper right hand figure : Euhaeniatopinus abnormis. 
