162 ORDER HEMIPTERA 



long, and with the antennae situated at the sides midway 

 from the posterior to the anterior borders; behind these 

 are located slight eminences upon which may be found the 

 small eyes, which are seen with considerable difficulty. At 

 the front of the head may be seen the small rostrum or beak, 

 the end of which is usually near the surface, but which is 

 capable of extension or retraction. The end of this beak is 

 armed with a double row of recurved hooks (see Fig. 115). 



Fig. 117. — Hoematopinus eurysternus: a, female; b, rostrum; c, ventral 

 surface of the last segments of the male; d, same of female; e, egg: /, surface 

 of same greatly enlarged. (Author's illustration, Bur. Ent., U. S. Dept. 



Ag.) 



Hog Louse {Iloematopiuus iirius). — The hog louse is one 

 of the largest species of the family, full-grown individuals 

 measuring a fourth of an inch or more in length. It is of a 

 gray color, with the margins of the head and thorax and 

 most of the abdomen dark. The head is quite long, the 

 sides nearly parallel, with strong eminences just back of 

 the antenna^, which are set on the sides of the head, midway 

 from rostrum to occiput; the legs are lighter, with dark 

 bands at the joints; the spiracles are inclosed by a black 



