84 M. O. Strobelt on the Anatomy and 



three times this length* In the male the terminal segment is 

 blunt, while in the female it is produced* on each side into a 

 process which is closely covered with hairs. Between these 

 processes the margin of the segment is straight. From the 

 middle of this straight termination the longitudinally cleft 

 genital fissure extends forward. The two abdominal pro- 

 cesses are united by a chitinous ring which bears a number 

 of shorter and longer hairs directed towards the genital orifice. 

 If w r e make a longitudinal section through the abdomen, 

 so as to divide it into a right and a left half, we see how 

 the last segment seems to be excavated. The epidermis 

 is firm and thick-scaled on both the dorsal and ventral 



sur 



faces. 



Internal Anatomy and Physiology. 



Integument. 



Hcematopinas tenuirostris has a yellowish, translucent, toler- 

 ably firm external chitinous envelope, which shows two layers 



an outer one, the epidermis ^ and an inner one, the cutis. 



The epidermis shows a different structure at different parts 

 of the body. Thus on the middle part of the back it appears 

 to consist of small rounded scales, pretty regularly arranged 

 in series, lying one over the other like the slates on a roof. 

 Towards the abdominal extremity these little scales gradually 

 become quadrangular, with the sides much curved, and are 

 separated from each other by double-contoured grooves. 

 Thence to the end of the abdomen we see small, triangular, 

 imbricated scutes, which not unfrequently run out into a 

 point. While on the dorsal surface a certain regularity ap- 

 pears in the arrangement of the scales and scutes, on the 

 ventral surface the epidermis is divided by much curved and 

 contorted furrows into multiform irregular sections, which give 

 the whole an exceedingly varied and elegant appearance. 

 The integument of the head is cut up by double-contoured 

 furrows into divisions of very different forms, but which always 

 more or less resemble hexagons, and may be referred to that 

 form. On the other hand, the epidermis of the limbs and 

 antennae shows no such divisions, but is simple. Besides the 

 elegant furrows, many thickenings are to be observed in the 

 integument. Thus on the dorsal surface a broad thick band 

 passes forward from the middle of the hinder margin of the 

 thorax, divides at about the middle of the thorax, and runs 

 up parallel to the margins of the occiput. Further, the bands 

 which run from the acetabulato the thickening just described, 

 as well as the acetabula themselves, are thickenings of the 



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