504 MEDICAL ENTOMOLOGY 



the posterior and larger of which is in front of the coxa of the second 

 leg. External to the coxa of this leg, and lying usually under cover 

 of the femur, there is a strong hooked process, probably representing 

 the episternum of the mesothorax. The narrowest part of the thorax 

 is at the junction of the first and second segments ; the metathorax 

 broadens out from before backwards and merges with the abdomen. 



The wings are represented by a pair of small elytra (Plate LXI, 

 fig. 5) which cover the greater part of the metanotum. Their dorsal 

 surfaces are strongly concave, and are covered with feathered hairs. 

 They are articulated with the lateral portions of the mesonotum. 



The legs are of moderate strength, and show the usual joints. The 

 coxa, trochanter, femur, and tibia resemble those of the Diptera, and are 

 easily recognized. On the inner side of the distal end of the tibia there 

 is a small 'aigrette' of fine hairs, arranged like a comb (Plate LXII, 

 fig. 6). The tarsus is said to consist of four joints ; the first is small, and 

 is separated from the larger second by an oblique articulation ; the third 

 is the largest, and is separated from the second by a definite notch on the 

 outer side of the limb, while the fourth is very small, and bears the claws. 

 The lines of demarcation between these joints are very faintly marked. 

 The claws are bilaterally symmetrical and simple, and are not very strong. 

 There are no pads on the feet like those with which the Diptera are 

 usually provided, and the bug is consequently unable to move easily on 

 smooth surfaces. 



The abdomen consists of eight segments in each sex, with some addi- 

 tional sclerites modified for sexual purposes. In the male the first seven 

 segments are simple, each consisting of a tergite and 

 (Plate LXI) sternite, the former of which overlaps the latter at the 

 sides; the segments decrease in width in a regular 

 manner from the third, the abdomen being distinctly more pointed in 

 the male than in the female. 



The eighth segment is asymmetrical, having a distinct notch on the 

 left side, for the accommodation of the penis. The latter organ (Plate 

 LXI, fig. 6) is shaped like a large claw, broad at the base and termi- 

 nating in a curved point, and is directed to the left side in the transverse 

 plane of the body, both in the position of rest and when extended. 

 It emerges from the abdomen through a short collar-like ring of chitin 

 which may represent a suppressed abdominal segment. 



The abdomen of the female is much rounder than that of the male, the 

 fifth segment being about as broad as the first. The genital opening is 

 situated on the ventral side anterior to the anus, and is bounded by the 



