*«T. :iu. STUDIES OF THE BITING LICE — EWING. 13 



a forked and furrowed tenaculum for holding tarsus. Tarsus II and 

 III each with second segment greatly elongated and transversely fur- 

 rowed and with the claw proper, which is greatly reduced, forming 

 a clawlike structure adapted for fitting into femoral tenaculum. 

 Tibia 1 without a row of toothlike setae on a swollen or thumb-like 

 expansion at the inner distal margin. Abdomen oval, typically each 

 segment with two transverse rows of setae. Sexual dimorphism 

 sometimes marked in case of male which has the first segment of 

 tarsus I produced inwardly and formed into a thumb which with 

 the accompanying claw forms a pair of claspers. 



Genotype and its host species. — Gyropus ovalis Nitzsch from Oavia 

 cobaya (guinea-pig). 



In this genus are included seven species of the subfamily Gyro- 

 pinae. Three of these, G. ovalis Nitzsch, G. forflcMlatus Neumann, 

 and G. alpinus Kellogg and Nakayama have been described, the 

 other four are new. 



KEY TO THE SPECIES OF GYROPUS EXAMINED BY THE WRITEE. 



a.* Dorsal setae of abdomen minute, not over one-fourth as long as the segments 



on which they are situated G. ovalis Nitzsch. 



a.' Dorsal setae of abdomen large, about as long as or even longer that the 

 segments on which they are situated. 



h.^ Second and third pairs of legs essentially the same; tenaculum of leg 



III with a conspicuous tuberclelike lobe; tibia III from two to three 



times as long as broad. 



c' Tarsal thumb of male longer tlian the width of the segment it is a 



part of, but slightly curved and but little broader at its middle 



than at its tip G. forficulatus Neumann. 



c." Tarsal thumb of male not longer than the width of the segment 

 it is a part of, strongly curved and much broader at the middle 

 than at the tip. 

 d^ Tarsal thumb of male not as broad at its middle as at its base, 

 moderately curved; a conspicuous chitinized penis present. 



G. pollicaris, new species. 



d.' Tarsal thumb of male as broad at its middle as at its base and 



strongly curved ; penis wanting— G. latipollicaris, new species. 



b* Third pair of legs more slender than the second, with femoral tenaculum 



greatly reduced and tuberclelilie lobe small; tibia of leg III at least 



four times as long as broad; tarsal claw of leg III longer and 



sharper than the claw of leg II. 



c* Abdomen fully twice as long as broad and with sides subparallel. 



G. gracilipes, new species, 

 c' Abdomen about one and a half times as long as broad, and oval. 



G. wetmorei, new species. 



GYROPUS OVALIS Nitzsch. 

 Text fig. 6. 



A medium-sized, short, oval species. Head (fig. 6) very broad; 

 temporal lobes large and projecting, with a tuft of three or four 

 setae at each angle. Antennae capitate, last segment spherical and 



