THE ACARINA OR MITES— BANKS. 



87 



the elytra. One species that has been recorded from this country, JL m /- 

 sarcoptes coecisngus Lignieres, is said to live among the eggs of 2fyfl- 

 lasjyis ponKynim. The principal genus is Canestrinia, represented by 

 live or six species. 



Family ANALGESID.E. 



The bird-mites {SarcoptkJrs pJum icohs of Megnin) form one of the 

 largest and best-known groups of the Acarina, Since the specimens 

 can be found on the skins of birds, collections have been made in 

 various nuiseums, so that many species occurring in tropical countries 

 are described — a condition not existing in other groups of mites, 

 except the Ixodidw. The species in the United States, however, have 

 been but little studied. The body 

 of an Analgesid is more or less elon- 

 gate; the skin is soft and trans- 

 versely wrinkled; in many forms 

 there are tinely granuhite dorsal 

 shields, one anterior, and a longer 

 posterior one; there are neither 

 eyes nor stigmata; there is usually 

 a distinction between cephalothorax 

 and abdomen. In front there is a 

 conical projection, the rostrum; the 

 upper part of this is known as the 

 epistoma, and is continuous with 

 the dorsal surface of the body. 

 Beneath the epistoma is a pair of 

 triangular simple mandibles, which 

 often project beyond it. The man- 

 dibles are commonly chelate, and 

 iinel V toothed at the tip. Below the 

 jaws are a pair of maxilhe, which 

 l)ear on their outer side the simple three- jointed palpi. Below this is 

 the lower lip, and between the two is a ligula or tongue. The legs 

 are commonly short and stout; they are arranged in two groups, the 

 anterior pairs close to the mouth-parts, the posterior pairs toward the 

 end of body. From their insertion on the venter there extend chitinous 

 brown rod-like pieces, the epimera, which form a framework or skel- 

 eton for the attachment of muscles and support of the legs. The legs 

 are of live joints, the last ending in a cup or saucer-shaped sucker or 

 amlnilacrum. Sometimes there are one or two claws. The legs bear 

 a few hairs or bristles, in a definite arrangement. The two hind 

 pairs of legs often diHer in the two sexes, and in the male one is often 

 enlarged or longer than the other, and used as claspers. Sometimes 

 there are projections or apophyses on the legs. In some forms there 



Fic. 167.— Analgesid; o, palpvs; b, caroncle; 



C. epimera; <^, GENITAL OPEMNG; f, PROCESS; 



/, ANAL suckers; g, lobe. 



