THE LOUSE. 



99 



capitis, the head louse; Fig. 113, P. vestimenti, the body louse) 

 with the young bed-bug as figured by Westwood (Modern. 

 Classification of Insects, ii, p. 475) we shall see a very close 

 resemblance, the head of the young Cimex being proportionally 

 larger than in the adult, while the thorax is smaller, and the 

 abdomen is more ovate, less rounded; moreover the body is 

 white and partially transparent. 



Under a high power of the microscope specimens treated 

 with diluted potash show that the mandibles and 

 maxilla) arise near each other in the middle of the 

 head opposite the eyes, their bases slightly diverg 

 ing. Thence they converge to the mouth, over 

 which they meet, and beyond are free, being hol 

 low, thin band^ of chitine, meeting like the maxilla}, 

 or tongue, of butterflies to form a hollow tube for 

 suction. The mandibles each suddenly end in a 

 curved, slender filament, which is probably used 

 as a tactile organ to explore the best sites in the 

 flesh of their victim for drawing blood. On the 

 other hand the maxillae, which are much narrower 

 than the mandibles, become rounded towards the end, bristle- 

 like, and tipped with numerous exceedingly fine barbs, by which 

 the bug anchors itself in the flesh, while the 

 blood is pumped through the mandibles. The 

 base of the large, tubular labium, or beak, which 

 ensheathes the mandibles and maxilla?, is oppo 

 site the end of the clypeus or front edge of the 

 upper side of the head, and at a distance beyond 

 the mouth equal to the breadth of the labium 

 itself. The labium, which is divided into three 

 joints, becomes flattened towards the tip, which 

 is square, and ends in two thin membranous 

 113. Body Louse, lobes, probably endowed with a slight sense of 

 touch. On comparing these parts with those of the louse, it 

 will be seen how much alike they are with the exception of the 

 labium, a very variable organ in the Hemiptera. From the long 



chitinous band, and c, the hind part of the lower lip, such as they appear through 

 the skin by strong transmitted light; dd, the foremost protruding part of the lower 

 lip (the haustellum) ; ee, the hooks turned outwards;/, the Inner tube of suction, 

 slightly bent and twisted; the two pairs of jaws are perceived on the outside as 

 thin lines; a few blood globules are seen in the interior of the tube. 



