XVIII HETEROSTIGMATA NOTOSTIGMATA 473 



(iv.) The Cheyletinae are remarkable Mites with fleshy, semi- 

 transparent body, and enormously developed raptorial pedipalpi, 

 which are extremely formidable weapons of attack. They do 

 not creep or run like most Mites but proceed by a series of short 

 leaps. Cheyletus is the principal genus. 



The curious genus Syringopliilus, which is parasitic in the 

 interior of birds' feathers, appears to be a degenerate Cheyletine. 



(v.) The Erythraeinae are minute, active Mites, usually red 

 in colour, free-living and predaceous. 



(vi.) The Trombidiinae include most of the moderate-sized, 

 velvety red Mites which are commonly known as " Harvest-mites," 

 and their larvae, the so-called Harvest-bugs, frequently attack 

 man. Trombidiwm Jiolosericeum is a well-known example. 



Sub-Order 6. Notostigmata.^ 



This sub-order has been established for the reception of the 

 curious genus OpUioacarus. 



Fam. Opilioacaridae. — Mites with segmented abdomen, leg- 

 like palps, chelate chelicerae, and two pairs of eyes. There 

 are four dorsal abdominal stigmata. Four species of the sole 

 genus OpUioacarus have been recorded, 0. segm.entatus from 

 Algeria, 0. italicus from Italy, 0. araMcus from Arabia, and 

 0. platensis ^ from South America. 

 1 With, Vid. Medd. 1904, p. 137. ^ Silvestri, Rcdia, ii., 1904, fasc. 2, p. 257. 



