466 ARACHNIDA—ACARINA CHAP. 
Fam. 1. Sarcoptidae.—No tracheae or stigmata. Apical 
rostrum. Oviparous or ovoviviparous. The seventy genera and 
530 odd species of this family are divided into a number of 
sub-families, of which the principal are the 
Sarcoptinae, the Analgesinae, and the Tyro- 
elyphinae. 
(i.) The Sarcoptinae are the so-called “ Itch- 
mites.” They are minute animals, with bodies 
transversely wrinkled and legs terminating in 
suckers or bristles. The genus Sarcoptes, 
which includes about fifteen species, lives in 
tunnels which it burrows in the skin of 
mammals. 
Gi.) The Analgesinae are the “ Birds’- 
feather Mites.” The principal genera are 
Pterolichus (120 species), Pteronyssus (33 
species), Analges (23 species), Megninia (42 
species), and Alloptes (33 species). 
(iii.) The Tyroglyphinae ' have received the 
popular name of “Cheese-mites,” from the 
best known example of the group. They 
are smooth-bodied, soft-skinned white Mites, 
with legs usually terminating in a single claw, 
sometimes accompanied by a sucker. They 
are for the most part carrion-feeders, living 
ete ee ee oe upon decaying animal or vegetable matter, 
“leg-scab” ; B, but a few are parasitic on mammals, insects, 
female of Sarcoptes and worms. 
mutans, greatly 
magnified. (After There are sixteen genera, including about 
et fifty species. Tyroglyphus sivo and T. longior 
are common Cheese-mites. Other species live in decaying 
vegetables and food-stuffs. Some of the genus Glycyphagus 
(G. palmifer, G. plumiger) are very remarkable for the palmate 
or plumose hairs which decorate their bodies. The remarkable 
hypopial stage in the development of Tyroglyphus has been 
mentioned on. p. 463. The Tyroglyphinae are the lowest of the 
free-living Acarine forms. | 
ae Oe 
Ba WD 
a 
1 See Michael, British Tyroglyphidae, published by the Ray Society, 1901-2. 
