ON A NEW PATHOGENIC LOUSE WHICH 
ACTS AS THE INTERMEDIARY HOST OF A 
NEW HAEMOGREGARINE IN THE BLOOD 
OF THE INDIAN FIELD RAT 
(JERBELLUS INDICUS) 
BY 
S. R. CHRISTOPHERS, M.B., (Vict.) 
I. M.S., The King Institute, Guindy, Madras 
AND 
R. NEWSTEAD, A.L.S., F.E.S., etc. 
_ (With one plate) 
HAEMATOPINUS STEPHENSI, n.sp. 
Male (fig. i). — Body rather slender. Head as broad as long, quad- 
rangular, posterior angles with a large flat chitinous expansion from which 
arises a stout hair extending backwards and reaching slightly beyond the 
insertion of the third pair of legs. Mentum with six short, curved spines, 
arranged in a circlet ; beyond the mentum is a bilateral series of three larger 
spines, arranged somewhat in the form of a circle. Mesothorax with two long, 
stiff hairs, widely separated. Antennae (fig. 2) stout, of five segments ; first 
segment much the largest, broader than long, the length equalling half the 
width of the head ; second 1 segment simple ; third segment the shortest, an- 
teriorly produced into a long, blunt, curved spine ; fourth segment simple, 
not quite as long as the second ; apical segment shorter than the fourth, apex 
truncate, bearing three or four minute spines ; margins of all the joints more 
or less highly chitinised. Leg i. shorter than the rest ; leg ii. (fig. 3) similar 
to leg i., but the tarsus is a little more dilated ; claw long and slender ; leg iii. 
much the stoutest ; terminal clasping-claw (fig. 4) large, apex blunt ; inner 
sub-terminal claw much smaller, and when closed lies completely hidden 
within a groove in the tarsal joint, a small stout spine arises from its base. 
Abdomen of nine segments, each segment furnished with a transverse series 
of long, stiff hairs, some of those at the margins being much the longest. 
Genital armature (see fig. 1) with a central, slightly curved, blunt, spine- 
shaped, or horn-shaped organ, on either side of which is a small setiferous 
lobe. , 
Female. — Head (fig. 5) much narrower than that of the male, somewhat 
rectangular, length greater than the width. Antenna (fig. 6) of five seg- 
ments ; basal segment much the widest, its length equalling about one-fourth 
the width of the head ; second segment the longest ; apical segment trun- 
cate and furnished with several minute hairs ; formula 2, 1, 4 (35) ; margins 
■ 
