60 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I23 



their morphological similarity in the female and relatively great simi- 

 larity in the male (as compared to the other species in the group) 

 indicate a probable relationship at the subspecific level. 



As further indication of the above, the aedeagus of each of the spe- 

 cies of the hamifer group shows differences believed to be at the species 

 level, considering the fact that equal variation, or even less, is found 

 among the other full species of the genus (i.e., draco, ebrighti, and 

 hesperomys). The aedeagus is similar in the various subspecies of 

 P. hesperomys, and the same is true for the subspecies of P. silvatica. 

 However, P. hamifer hamifer, P. hamifer vigens, and P. hamifer 

 cuneata ssp. nov. differ from one another insofar as amount and place- 

 ment of spiculation on the lateral lobes are concerned. (See figs. 117, 

 118, and 126, L.L.) 



PEROMYSCOPSYLLA TIKHOMIROVAE (loff, 1946) 



Figures 91-98, 121 



Leptopsylla tikhomirovae Ioff, in loff, Tiflov, et al., Meditsinskaia, parazitologiia- 



i parazitarnye bolezni, Moscow, vol. 15, No. 4, p. 91, 1946. 

 Peromyscopsylla tikhomirovae Hopkins and Rothschild, in MS. 



Head (fig. 91). — Not as bullet-shaped as in other members of the 

 genus. No spiniforms on preantennal area ; with four anteromarginal 

 bristles and a row of three subdorsal bristles commencing at frontal 

 angle ; in addition, five nonmarginal bristles (three missing in speci- 

 men drawn). Spines of genal ctenidium more slender than is usual in 

 genus, upper genal spine the longer, obscuring genal process; genal 

 lobe apparently undeveloped. Second antennal segment with bristles 

 reaching end of club in both sexes. Postantennal area with three rows 

 of bristles. 



Thorax. — As in hesperomys, except bristles relatively fewer on 

 mesonotum (fig. 92) ; few bristles present anterior to four complete 

 rows, and no erect bristles dorsally. 



Abdomen. — Anterior row of bristles present only on terga i and 

 2 in male, this row represented by one or two lateral bristles in 

 female. Male and female with three antepygidial bristles. 



Male (fig. 94). — Tergum 8 {8T.) with row of three large bristles 

 posterior to spiracle. Eighth sternum {8S. and fig. 97) peculiar, 

 apically long and narrow, and upcurved (reminiscent of ninth ster- 

 num of some rhopalopsyllids) ; apical half of extension with a ven- 

 tromarginal row of fairly long bristles plus four or five small mesal 

 bristles ; with two large subventral bristles proximad to elongate por- 

 tion ; membranous process not visible (this area in only available speci- 



