6 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63. 



tuft of hair for observation under the binocuhir microscope. It 

 proved to be a large female specimen of G forceUi with two males 

 holding on to her. One male was on each side, and both of them 

 were clasping the female with the two posterior pairs of legs. The 

 female was api:>arently but little inconvenienced by her heavy load 

 and moved easily about up and down the hairs. 



One of these males was observed in an unsuccessful attempt to 

 mate with the female. The genitalia with its ejaculatory sac was 

 protruded and held extended for a few seconds, but no connections 

 being made, was easily and quickly withdrawn. 



What appeared to be a normal mating was observed through the 

 binoculars on the host itself. The male clasped the abdomen of the 

 female with his two posterior legs from below, holding himself un- 

 der the female and his head under her thorax. In this position he 

 interfered very little with the locomotion and general activities of 

 the female, she packing him with facility as she crawled about in 

 the fur of the host. 



DESCRIPTIONS OF SUBFAMILIES, GENERA AND SPECIES. 



In the following pages descriptions are given of the three sub- 

 families and nine genera, which the writer recognizes as belonging 

 to the family, and of all the species represented in the combined 

 Washington collections. Mention iis made also of the known re- 

 maining species, and they are in nearly every case given in the 

 keys. 



KEY TO SUBFAMILIES AND GENERA. 



a \ Palpi composed of three segments ; tarsi normal PROTOQYROPINAE. 



Contains but one genus Protogyropus, new genus. 



a^ Palpi two, or four segmented ; at l^east one of the two posterior pairs of 

 legs modified so that each leg of a pair forms a hair-clasping apparatus. 

 6\ Palpi four segmented; second tarsal segment of second, and sometimes 

 the third pair, of legs much enlarged, clawlike and transversely stri- 

 ate ; femora of same legs each with a large, posterior, basal protuber- 

 ance which is forked and transversely striated for the reception of 



tarsus GYROPINAE. 



c \ Tarsus I provided with a single claw. 



d \ Femur of leg III without forked and striated tenaculum for 

 holding tarcus ; second segment of tarsus III not transversely 



striate Monogyropus, new genus. 



d^. Femur of leg III with tenaculum and tarsus III transversely 

 striate. 

 e\ Most of abdominal segments provided dorsally with one 

 or two transverse rows of subequal setae. 



f \ Typically each abdominal segment with two transverse 



rows of dorsal setae Gyropus Nitzch. 



/'. Typically each abdominal segment with a single trans- 

 verse row of dorsal setae Allogyropus, new genus. 



