136 



This does not include a few other specimens of different species 

 taken from Mus rattus and Mus norvegicus, which have been included 

 under the heading of " Enumeration of fleas which have been found 

 on rats." 



SYNOPSIS OF FLEAS COMMONLY FOUND ON RATS. 



A. WITHOUT A COMB OF SPINES ON THE PROTHORAX OR THE HEAD. 



1. Two bristles on the gena, an ocular bristle placed below the eye, an oral bristle 



placed just above root of maxilla. Meso thorax not divided by an internal 

 incrassation. Claspers in male forming prominent hump, claw like and cov- 

 ered by hairy flap. An irregular row of about 10 teeth on inner side of hind 

 coxa ......................................................... Pulex irritans. 



2. Two bristles on gena, an ocular placed in front of and just above middle of eye, an 



oral bristle placed just above root of maxilla. Mesothorax divided by internal 

 incrassation, claspers not forming prominent hump, not claw like, not covered 

 by hairy flap. A regular row of about six teeth on inner side of hind coxa, 



Lcemopsylla cheopis. 



AA. WITH A COMB OF SPINES ON PROTHORAX BUT NOT ON HEAD. 



3. Three bristles on lower genal row, upper genal row represented by three or four 



small bristles running along anterior margin of antennal groove. Eye present, 

 about five hairs on second joint of antenna, not as long as third joint. Maxillary 

 palpi not as long as labial palpi. Labial palpi reach to apex of fore coxa. Spines 

 on posterior tibia in pairs of about five groups. Head of male flattened on top, 



Ceratophyllus fasciatus. 



AAA. WITH A COMB OF SPINES ON THE PROTHORAX AND ON THE HEAD. 



4. Eye present, seven spines on lower margin of gena. Spines on posterior border 



of tibia in pairs ................................... Ctenocephalus cam's orfelis. 



5. Eye absent, four spines on hind margin of gena. Spines on posterior tibia single 



and in a close-set row ................................... Ctenopsyllus musculi. 



DESCRIPTION OF PLATE II. 



Fig. I. Clasping organs of male. 

 Fig. 2. Head of female. 



P ........... Process. 



F ........... Finger. 



M .......... Manubrium. 



IX St ....... Ninth Sternite. 



ST .......... Eighth Tergite. 



8 St ......... Eighth Sternite. 



Fig. 3. Terminal abdominal segments, female.. .. 



10 fet ........ 1 enth Sternite. 



Sp .......... Spermatheca 



Sty ......... Stylet. 



Fig. 4. Hind tibia. 



CERATOPHYLLUS FASCIATUS Bosc. 



[Plate II.] 



Head. Evenly and gently rounded in the female, flattened on top 

 in the male. Frontal notch distinct. Eye present, placed low down 

 in head. Gena acutely pointed posteriorly. Maxilla triangular. 



