Phys iology o/* Hsematopinus tenuirostris, Barm. 83 



Phthirtus and Pediculus the thoracic stigma is to be referred 

 to the prothorax. 



The legs are all constructed upon the same type. The 

 coxa is freely movable in the acetabulum, and is a stout 

 joint furnished with powerful muscles (fig. 6, c). This is 

 followed by the trochanter (fig. 6, tr) y which is not half so 

 large and not very muscular. Freely movable upon this, 

 next comes the large femur, bearing at its extremity the 

 powerfully-developed tibia (fig. 6, ./and ti). The latter has 

 not, as in the other lice, a chitinous process directed forwards, 

 but is simply elevated at the inner angle (fig. 6, e). At this 

 point, however, the chitinous skin shows a slight thickening, 

 behind which the tibia appears to be excavated. The above- 

 mentioned elevation of the tibia at the inner angle is more 

 considerable on the hinder pairs of legs, reduced to a mini- 

 mum on the first pair (fig. 1). Moreover the legs of the first 

 pair have a scarcely perceptible chitinous thickening at this 

 point. On all the pairs of legs, however, this process bears 

 a number of hairs. The tarsus, which follows the tibia, is 

 two-jointed, the first joint considerably narrower than the 

 tibia, and only about half its length. The second joint con- 

 sists of a somewhat curved claw, which is narrow and light- 

 coloured and terminated in a point on the first pair of legs, 

 in the other two pairs broad, dark brown, and rounded at the 

 end (fig. 6, ta, k } and fig. 1). 



The abdomen is separated by a distinct furrow from the 

 thorax, and consists of nine segments, which, however, exter- 

 nally are marked off from each other very faintly by indenta- 

 tions. Neither Denny nor Giebel give the number of the 

 abdominal segments ; but Denny (10, pi. xxv. fig. 8) figures 

 eight of them, having evidently overlooked the ninth, very 

 small segment, while Giebel (13, Taf. ii. fig. 9) represents 

 ten segments, the first of which must be referred to the thorax. 

 It is certainly the case that by mere external examination one 

 may very easily be in doubt whether eight or nine segments 

 are present; but the preparation of the muscles (musculi 

 transversales) at once shows that the number of segments is 

 nine. The first segment, as also the eighth and ninth, bear 

 no stigmata ; the other six have each one on each side, slightly 

 turned towards the ventral surface. The hairiness is in 

 general short and scanty ; on the abdomen the hairs are 

 scattered irregularly, and it is only in the vicinity of the 

 stigmata that some regularity appears. Thus beneath each 

 stigma there stand two hairs, which, in the case of the first 

 three on each side, do not exceed the other hairs in 

 length, but in that of the three hinder ones attain twice or 



