14 MISC. PUBLICATION 5 00, U. S. DEPT. OF AGRICULTURE 



Besides the name Siphonaptera, which should be attributed to 

 Latreille, two other names have been commonly applied to the fleas, 

 Aphaniptera Kirby and Suctoria Ketzius. In the selection of the 

 names of orders more consideration should be given to appropriate- 

 ness and usage than to priority. Hence, in this work the term 

 Siphonaptera has been used. 



The fleas have been divided into from three to about six families 

 by most modern workers. All workers recognize the families Puli- 

 cidae and Ischnopsyllidae, and two other families are usually recog- 

 nized, one containing the genus Oeratophyllus and related genera and 

 the other containing the degenerate genus Tung a and related genera. 



Wagner (86) has surpassed all others in the number of families 

 and subfamilies he has recognized for the order. He recognizes 10 

 families and 28 subfamilies, in addition to many tribes. Since many 

 of these subfamilies and tribes contain but a single genus each and 

 many are hard to separate properly on morphological characters, a 

 more conservative and usable classification appears desirable. 



Key to the Families and Subfamilies of Siphonaptera 



1. Thorax not greatly reduced, thoracic terga taken together longer than 



first abdominal tergum ; gravid females moderately, if at all, 



enlarged 2 



Thorax greatly reduced, thoracic terga taken together shorter than 

 first abdominal tergum ; females sometimes with a reduced number 

 of abdominal spiracles, and when gravid, abdomen greatly dis- 

 tended Hectopsyllidae Baker. 



2. Gena not divided by a vertical suture ; head without helmet 3 



Gena greatly enlarged, being extended dorsally in front of antennal 



groove and divided by a vertical suture ; head with a helmet com- 

 posed of the greatly reduced front and anterior parts of the greatly 

 enlarged genae ; postantennal region of head with a dorsal incrassa- 

 tion Stephanocircidae Wagner. 



3. Typical abdominal terga each with more than 1 transverse row of 



setae; fronto-epicranial groove frequently present 4 



Typical abdominal terga each with but 1 transverse row of setae ; 

 fronto-epicranial groove usually absent ; eyes usually present. 



Pulicidae Stephens 12 



4. Head seldom elongated, ventral flaps absent. Not parasitic on bats 5 



Head usually elongated, always with 2 or 3 ventral flaps on each side 



adjacent to fronto-genal angle. Parasitic on bats. 



Ischnopsyllidae Wahlgren. 



5. Cephalic combs absent ; front not reduced ; abdominal combs rarely 



present ; abdominal apical spines rarely numerous. 



Dolichopsyllidae Oudemans 6 

 Cephalic combs present ; front frequently reduced ; abdominal combs 

 frequently present; abdominal apical spines frequently numerous. 



Hystrichopsyllidae Baker 9 



6. Frontal notch or frontal tubercle, or both notch and tubercle, present 



(although sometimes vestigial) 7 



Frontal notch and frontal tubercle absent, there being no vestige of 

 either Uropsyllinae Oudemans. 



7. Antepygidial bristles absent or very poorly differentiated; abdomen 



frequently distended in female Vermipsyllinae Baker. 



Antepygidial bristles present, conspicuous; abdomen not distended; 

 labial palpus usually with 5 or less segments 8 



8. Pronotal comb absent Rhopalopsyllinae Oudemans. 



Pronotal comb present Dolichopsyllinae Oudemans. 



