REVISION OF THE SARCOPSYLLIDAE 43 
Jumping power reduced or absent. Tibiae without bristles on the lateral 
surfaces, or only one or two. Hind femur on inner side with a row of four or more 
bristles, the number seldom reduced to two. Three to seven pairs ot dorsal bristles 
on hind tibia. No hairs on the ventral surfaces of the tarsi, except at the sides ; 
first segment shorter than second in fore and mid tarsi ; fifth segment usually with 
two short bristles ventrally at the apex, standing close together, in some species one, 
in others none ; three to eight lateral bristles on fifth segment. Claw with or with- 
out basal projection. 
Eight sternite large. Clasper with three processes, the second and 
third forming a kind of pincers, uppermost process absent in Dermatophilus. Ninth 
sternite ' boomerang '-shaped, or the internal, vertical, arm of the elbowed sternite 
vestigial or absent, the sternite separated in the mesial line, except at the proximal 
ventral angle. 
%. Seventh sternite simple. Eighth tergite large, sternite very small. 
Stylet absent or present. One bursa copulatrix. Ten stigmata, except in $ Derma- 
tophilus, where the abdominal segments two and three have no stigma. 
The early stages are known only ot one species : Dermatophilus penetrans (see 
this species). 
Key to the genera : — 
(a) Hind coxa with patch of spines on inner side, Echidnophaga. 
„ without such a patch of spines — b y 
(b) Hind femur with large basal tooth-like projection, Hectopsylla. 
„ simple, Dermatophilus. 
I. Genus ECHIDNOPHAGA 
Sarcopsyllus Westwood (non Sarcopsylla id., 1840), Ent. Mo. Mag. XI. p. 246 (1875). 
Sarcopsylla, Taschenberg, Die Flohe p. 5 (1880) (partim). 
Echnidnophaga Olliff, Proc. Linn. Soc. N.S. Wales (2). I. p. 172 (1886) (type : E. ambulans). 
Argopsylla Enderlein, Deutsche Tiefsee — Exp. III. 7. p. 263 (1903) (type: Sarcopsyllus gallinaceus 
Westwood) . 
Xestopsyila Baker, Proc. U. S. Nat. Mus. XXVII. p. 374 (1904) (type : Sarcopsyllus gallinaceus 
Westwood) . 
$ Frons angulate ; a horseshoe-shaped transverse depression behind the 
angle. An internal incrassation of the skeleton from the base of the antennal groove 
upwards to the mesial line of the head. Two bristles on the frons, with a minute 
hair in between, the upper bristle in front of the eye. Occiput reduced in length. 
Eye more or less widely separate from the antennal groove. Posterior genal process 
long, separating more or less completely the prostcrnite from the antennal groove. 
Labium and labial palpus mostly not separated by a joint (suture). 
