878 SOME POINTS OE GENERAL INTEREST 
in the neighbourhood of dwellings, this statement needs 
confirmation. 
Distinguishing Characters of Genus Loemopsylla 
1. Pour segmented labial palps. 
2. Closed antennal groove. 
8. Anteriorly solid antennal club. 
4. Position of dorsal apical bristle of the seventh abdominal 
tergite remote from the edge of the segment. 
5. Presence of short spines on the inner surface of the hind 
coxa. 
6. The division of the rodlike incrassation inside the mid 
coxa taking place near the base. 
7. The structure of the modified abdominal segments. 
8. Two mandibles slenderer and longer than in P. irritans. 
Genus Pulex. Species — one only. P. irritans 
1. Chief character, greatly reduced thorax. Mesosternite 
(i.e. sternum) highly specialised, narrow, strongly oblique, 
and lacks the internal cariniform incrassation found in other 
fleas in compensation. The anterior ventral portion of the 
mesosternite is much strengthened inside. 
2. Male genitalia like Sarcopsyllidae, and not in other 
species, i.e. second and third processes of the claspers form a 
kind of claw. 
8. Bristle in front of eye, in most other species, is absent 
in P. irritans and is replaced by one below the eye. 
4. Hind coxa is distinguished from that of any known flea 
by bearing a number of hairs on the inner surface of the posterior 
(meral) portion. 
5. Has a small tooth (often absent) at the genal edge of 
the head slightly behind the lower oral corner. Genal portion 
— below eye from oral edge to antennal groove. 
Human Plague 
We will now shortly glance at plague as it affects man. 
There are two main forms of plague : Pestis minor , which is a 
