CHAPTER XXV 



Order Acarina (continued) : The Mites 



Family Gamasi'dcs; Insect-mites. The species of this 

 large family are quite like small IxodincB, but the chelicerae 

 are either chelate or styliform and are often exsertile and 

 retractile ; the pedipalps usually consist of 5 segments ; the 

 hypostome is styliform, the hind margin of the body is never 

 festooned ; eyes are never present, and the stigmata are 

 placed above and behind the coxae of the third pair of legs. 



Some of the Gamasidce are predaceous on mites and 

 small insects ; others are parasitic, mostly on insects, but also 

 on mammals, particularly on bats, and on birds ; and certain 

 species live in ant-nests. Raillietia lives on the ears of 

 cattle and horses. Dermanyssus is parasitic on birds; one 

 species {D. gallincB) attacks fowls, hiding in crevices by day 

 and emerging to suck blood at night ; this and other species 

 of Gamasidae occasionally attack man. Pneumonyssus was 

 found in the lungs of a monkey. Rhinonyssus occurs in the 

 nasal cavities of birds. Of the GamasidcB found on flying 

 insects, many, it is thought, are not truly parasites, but 

 merely use the insect as a means of transport. 



Family Uropodidce ; Stalked-mites. Minute predaceous 

 mites very much like Gamasidce, but having the spiracles 

 behind the second pair of legs. The retractile, chelate 

 chelicerae are of relatively enormous length. The nymph 

 attaches itself to insects, as a means of transport, by a long 

 viscid stalk which is secreted by a pair of adanal glands — 

 hence the name of the family. 



Family Trombidiidce. The typical members of this 

 family are large bright red mites, known from the nature of 

 their integument as Velvet-mites; their pedipalps (Fig. 127) 



