REVISION OF THE SARCOPSYLLIDAE 
i9 
III. Family Ceratopsyllidae Baker (1905). 
Head on each side with two flaps situated at the frontal oral corner. Here 
belong the bat-fleas only (Ischnopsyllus*). 
There are doubtless many more species of Sarcopsyllidae to be discovered. It 
may therefore ultimately be found necessary to divide the family into more than three 
genera. There is, however, at present no need at all for further division. By keeping 
such species, for instance, as Hectopsyha psittaci and pulex each in a separate genus, and 
proposing new genera for some of the other species which are similarly different, the 
natural division of the family into three sharply defined groups of species would only 
be obscured and no legitimate purpose served. 
Though there is a great diversity among the species of Saucpsyllidae in general 
appearance as well as in the details of structure, the family is so well characterized that one 
cannot possibly have any doubt about a flea belonging to this family or not. It is true, 
there are several peculiar characters which the Sanopsvllidae share with certain other 
fleas, for instance, the swelling of the abdomen of the pregnant females and the loss of 
the basal projection of the tarsal claws. However, the remarkable reduction of the 
rostrum (labium and labial palpi), not in length but in chitinization and segmentation, 
is nowhere else observed, nor are the thoracic tergites anywhere so much reduced as 
in this family. The similarities existing between the Sarcopsyllidae and members of 
the second (or central) family of Siphonaptera, the Pulicidae, are such as to render it 
practically certain that the similarities are partly the outcome of convergent develop- 
ment and partly indications of blood-relationship between the Sarcopsyllidae ami the 
Pulicidae. This is, in our opinion, best demonstrated by a general comparative 
description of the morphology of these insects. 
The head ot the Siphonaptera is divided by the antennal groove into an 
anterior or frontal portion (hereafter referred to as the frons) and a posterior or occi- 
pital portion (hereafter referred to as the occiput). The antennal groove is usually 
prolonged dorsally as a narrow slit in the of Siphonaptera, the grooves of the two 
sides of the head often meeting on the top. There is normally also an internal in- 
crassation of the skeleton from the groove upwards in both sexes. This arrangement 
is well marked in the Sarcopsyllid genus Echidnophaga. In the genera Hectopsylla and 
Dermatophilus the dorsal prolongation of the antennal groove and the internal 
thickening of the chitin are absent in both sexes, the genera Dermatophilus and 
Hectopylla being in this respect more specialized than Echidnophaga. Such a speciali- 
zation is not confined to these two genera of Sarcopsyllidae. We meet with it also 
among the Pulicidae in the genera Chaetopsylla and Vermipsylla. 
The frons and the occiput of the Sarcopsyllids (PI. I, Fig. 1-5), like those of 
the true Pulicids, bear dorsally and dorso-laterally a number of deep punctures, each 
puncture being provided with a short hair. 
* Westwood, Entom. Magax. i. p. 362 (1833) (nom. indescr.) ; id., Intr. Classif. Jus. ii., Syn. p. 125 (1840). 
