ACAE1NA 



439 



E. vitis (Landois) (Fig. 689). Produces an erineum on the under 

 side of grape leaves, which causes a swelling on the upper side; length 

 .16 mm.; width .032 mm. 



E. quadripes (Shimer). Produces round galls on 

 leaves of the soft maple. 



FAMILY 2. DEMODICIDAE.* 



Body minute and worm-like, the hinder part being 

 greatly prolonged and ringed; eyes and tracheae absent; 



4 pairs of 3-jointed legs; pedipalps close against the ros- 

 trum ; anus just back of the hind legs : 1 genus with about 



5 species. 



DEMODEX Owen. With the characters given above: 

 several species, which live in sebaceous glands and hair 

 follicles of man and the domestic animals. 



D. folliculomm Simon (Fig. 690). Length .4 mm. or less; width 

 .05 mm.: in the skin of the human face, supposed to be the cause of 

 " blackheads "; also in cattle and hogs. 



D. bovis Stiles. Length .25 mm.; width .064 mm.: in the skin of 

 cattle, causing swellings of the size of a pea in the hide. 



FAMILY 3. SAECOPTIDAE.* 



Itch mites. Body minute, globular, or ovoid in shape, finely striated 

 on the surface and with a few long bristles; eyes and tracheae absent; 

 legs short, each ending in 1 or 2 claws or a stalked or sessile sucker or a 



Fig. 690 



Demodex 



folliculorum 



(Banks). 



Fig. 691 Sarcoptes scabiei (Banks). A, dorsal aspect of female; B, ventral aspect 

 of male ; C, a mite in its burrow. 



bristle; pedipalps close against the rostrum; mandibles usually chelate: 

 in the skin of mammals and a few birds, causing itch and mange. The 

 female burrows through the skin, feeding on the tissues, and leaving a 

 row of eggs behind her, and finally dies at the end of her burrow. The 



See "Demodicidae et Sarcoptidae," Das Tierreich, 1899. 



