440 



ARACHNIDA 



young female on being fertilized 



starts a 

 About 100 



buiTow and thus a host 

 species, 13 species being 



Fig. 692 

 Psoroptes ovis — ■ 

 female (Banks). 



becomes infested in patches. 

 American. 



1. Sarcoptes Latreille. The first two pairs of legs end with 

 stalked suckers and in the male the fourth pair also; the others end 

 each with a long bnstle ; mandibles chelate : in mammals, 

 burrowing in the skin; about 14 species, 6 American. 

 S. scabiei (DeGeer) {S. Jiominis Hering). Itch mite 

 (Fig. 691). Length of female .45 mm.; width .35 mm.; 

 male half as large; egg .14 mm. long: causes itch in 

 man and mange in hogs. 



S. canis Gerlach. Mange mite. Length of female 

 .48 mm.; width .35 mm.; egg .17 mm. long: causes 

 mange in dogs, also in maa. 



S. cati Hering. Mange mite. Length of female 

 .25 mm.; width .2 mm.; egg .1 mm. long: causes mange 

 in cats. 



2. Psoroptes Gervais. Mandibles adapted for 

 piercing and not burrowing; stalks of leg suckers jointed: on the 

 surface of the skin of mammals, where they suck blood; 5 species. 



P. ovis Hering. Scab mite (Fig. 692). Length of 

 female .60 mm.; width .40 mm.; egg .2 mm. long: on 

 sheep, cattle, and horses, causing scab; the eggs hatch 

 in 2 or 3 days and the young mature in 15 daj's; the 

 females live several weeks, laying numerous eggs; an 

 infection thus spreads very rapidly and may cause the 

 death of the host; common in the west. 



3. Chorioptes Gervais. Females with suckers on 

 the fourth pair of legs: on the surface of the skin of 

 mammals, being restricted to certain parts of the 

 animal; 2 species. 



C. communis Ziirn. Length of female .42 mm.; width .27 mm.: 

 causes local inflammation in the ears of dogs, cats, and rabbits. 



4. Cnemidocoptes Fiirst. Female without suckers on any of the 

 legs; mandibles chelate: on birds; 2 American species. 



C. mutans Robin (Fig. 693). Length of female .45 mm.; width .35 

 mm. : the itch mite of fowls, causing scaly leg, but also appearing among 

 the feathers. 



Family 4. ANALGESIBAE. (Dermaleichidae.) 



Bird mites. Minute mites with an elongated body, a transversely 

 striated integument and often a transverse suture between the front 2 



Fig. 693 



Cnemidocoptes 



mutans 



(Banks). 



