558 PHYSIOLOGY. 



gums of the deer, as well as Gastrus nasalis, attacks, besides the 

 horse, likewise the ass, mule, deer, and goats. Beyond Europe we 

 also find several species, one of which, Trypoderma cuniculi, Wied, 

 ((Estrus cuniculi, Clark) lives beneath the skin of North American 

 hares and rabbits. (Eatrus buccatus, Fab., and Musca Americana, 

 Fab., likewise belong to this genus, established by Wiedemann, and 

 without doubt live in a similar manner. The genus Colax, Wied., 

 which is native to the Brazils and Java, admits of presuming a similar 

 mode of life, from its affinity to them. 



The mammalia, which feed upon insects, are less numerous than the 

 insectivorous birds. We will enumerate as such the smaller Makis, 

 for example, the genera Stenops, Otolicnus, the last of which lives 

 especially upon grasshoppers ; the majority of indigenous bats, the 

 shrew, the hedgehog, mole, and the other genera belonging to theforis 

 insectivori. Besides, very many of the Edentata, namely, Dosypus and 

 Manis, feed upon insects. The species of the allied genus Myrmeco- 

 pliaga, devour only ants, which they lick up with their long vermiform 

 tongue, like the woodpecker among the birds. 



310. 



There still remains, as the subject of a short notice, the relation 

 existing between insects and man. The human body, like that of the 

 mammalia, serves as a residence for several parasitic insects. The best 

 known and most generally distributed parasites are the lice, four 

 species of which man nurtures in different parts of his body. The 

 most numerous of these is the head louse (Pediculus capitis), which 

 lives in the hair of the head of many children, and of such adults who 

 are not clean, where it pierces the skin and sucks the blood. It prefers 

 the inclined parts of the head, and especially the back of the head, 

 where it deposits its eggs (nits), which are little pear-shaped bodies, 

 which it fastens to the base of the hair by means of a clammy substance. 

 The clothes louse (Pedic. vestimenti, De Geer), which differs from the 

 head louse by its larger size, more slender form, and by having black 

 spots upon the sides of its body, dwells upon the whole surface of the 

 body, but not upon the head, preferring particularly the breast and 

 back, and is less general than the former, and only found in very dirty 

 people among the lowest classes; it is exceedingly abundant in Poland 

 and Russia. It lays its eggs at the base of the small hairs of the skin, 

 and conceals itself upon the skin and in the folds of the vestments. A 



