84 A HALF HOUR WITH TflS 



us are certain insects which are more frequently 

 discovered than acknowledged. However dis- 

 agreeable their presence may be, they become 

 interesting objects for microscopic investigations, 

 and are not less calculated to excite our admira- 

 tion than creatures more ceremoniously treated. 

 We first call attention to the common flea (Pulex 

 irritans). This beautiful insect belongs to a large 

 family, each species of which has its peculiar habitat 

 in the epidermal appendages of some of the higher 

 animals. The head of the human flea may be taken 

 as the type of the family. This is represented with 

 great accuracy at figure 195, in plate 7. It is 

 furnished with antennae, mandibles, and a pair of 

 lancet-shaped jaws, with which it makes little 

 wounds in the skin, and into which it pours the 

 irritating secretion which renders its bite a source 

 of annoyance. Its eye, large hind legs, and orna- 

 mental saddle on its back, are all deserving of 

 attention. 



Let us now seek another too common inhabitant 

 of London houses, the bed-bug (Cimex lectularius), 

 and, having decapitated him, submit his head to a 

 low power. He, too, is a biting creature ; and you 

 will observe, as drawn in figure 196, that his jaws 

 are finer than those of the flea, and are like a pair 

 of excessively fine sharp hairs ; they are inclosed in 

 a sheath, from whence they are projected when 

 used. In the same sheath is the tongue, which 

 performs the double office of depositing in the 

 wound an acrid and irritating secretion and suck- 

 ing up the blood of its victim. The antennae and 

 eyes of the bug are also worthy of examination. 

 From the latter will be found projecting minute 

 hairs. 



A still more despised animal may now be sought 

 (Pediculus). It also belongs to a large family, and 



