NO. 4 FLEA GENUS PEROMYSCOPSYLLA — JOHNSON AND TRAUB 7 



Movable finger usually broadest above middle, definitely less than 

 tviro times as long as broad (figs. 29-31, F.) (southwestern 

 United States, Rocky Mountains, and east to Alberta, the Da- 

 kotas, Colorado, Texas) hesperomys adelpha (Rothschild), p. 17 



KEY TO FEMALES OF THE GENUS PEROMYSCOPSYLLA 



1. No spiniforms at frontodorsal angle of head (fig. 91) 2 



Two or more spiniforms at frontodorsal angle of head (fig. i) 3 



2. Second antennal segment with extremely short bristles (not reach- 



ing past second segment of club) ; pedestal of antepygidial bristles 

 divided, so that there is a gap between upper two bristles and ven- 



tralmost bristle (fig. 102) hinmlaica (Rothschild), p. 62 



Second antennal segment with apical bristles reaching end of club; 

 pedestal of antepygidial bristles not divided. .. Jikhomirovae (loff), p. 60 



3. Genal process hidden by upper genal spine ; three dorsosubmarginal 



bristles between spiniforms and antennal groove (fig. 74) 4 



Genal process visible above upper genal spine (fig. i, G.P.) ; two 

 dorsosubmarginal bristles between spiniforms and antennal groove 6 



4. No row of short bristles above spiracle on eighth tergum 



hident-ata (Kolenati), p. 54 

 Row of five or six short bristles above spiracle on eighth tergum 5 



5. Posterior margin of seventh sternum with long narrow lobe at least 



one-half as long as bristles in row on the sternum (fig. 84) 



( Siberia) ostsihirica ostsibirica ( Skalon) , p. Si 



(Alaska) ostsibirica longiloba (Jordan), p. 53 



Posterior margin of seventh sternum with lobe subtriangular ; its 

 length no more than one-third that of bristles in row on the 

 sternum (fig. 75) 

 (North America, east of Rocky Mountains) 



hamifer hamifer (Rothschild), p. 43 

 (North America, Rocky Mountain region) 



hamifer vigens (Jordan), p. 47 

 (Asia, Korea) hamifer cuneata, new subspecies, p. 49 



6. Upper genal spine the longer (fig. 59) 7 



Upper genal spine the shorter (fig. i) g 



7. Preantennal area of head with six long bristles (discounting mar- 



ginals and subdorsals) (fig. 55) selcnis (Rothschild), p. 31 



Preantennal region with five long bristles (discounting marginals 

 and subdorsals) (fig. i) 8 



8. Apical bristles on second antennal segment extremely short, not 



reaching apex of second segment of club; rows of bristles on 



postantennal area of head irregular (fig. i) cafatina (Jordan), p. 34 



Bristles on second antennal segment three-fourths length of club ; 

 four regular rows of bristles on postantennal area of head 



(fig- 74) 



(European continent, Asia) silvatica silvatica (Meinert), p. ^6 



(British Isles) silvatica spectabilis (Rothschild), p. 39 



(European Alps) silvatica fallax (Rothschild), p. 41 



9. Genal lobe less than one-half length of lower genal spine (fig. 43, G.L.) . .10 

 Genal lobe more than one-half length of lower genal spine (fig. i, G.L.) ... 12 



