290 ENTOMOLOGY FOR MEDICAL OFFICERS 



and lime, and greasy applications containing tar, sulphur, 

 precipitate of mercury, or plain petroleum. Infected yards, 

 stables, fowl-houses, etc., should be thoroughly washed out 

 with any good insecticide solution that is available, and then 

 tarred or white-washed. 



The other subfamilies of SarcoptidcB are the following : — 



(2) Canestriniincz. Parasites of beetles and other insects. 



(3) Analgince ; Bird-mites. Usually living on the feathers. 

 The body is often fantastically shaped. One species is known 

 to have a Hypopus stage (see p. 291), in which it burrows 

 into the subcutaneous areolar tissue and even into the air, 

 passages of its host. 



(4) ListiophorincB. Parasites of bats and other small 

 mammals. The body is curiously shaped, and some of the 

 appendages are specially modified for grasping the hairs of 

 the host. 



(5) CytolichincB. Parasitic on fowls. They resemble the 

 itch-mite but have a smaller rostrum. They sometimes 

 burrow into the subcutaneous areolar tissue, and invade and 

 even obstruct the air-passages. 



'' Family Tarsonemidcs. A small family of minute, soft- 

 bodied, usually transparent mites, parasitic on plants, to 

 which they cause much damage. The mites may creep on 

 to men handling infested plants, and may give rise to 

 erythema and intolerable itching, due probably to some 

 venomous secretion. In this family the chelicerse are 

 needle-like, the pedipalps are hardly visible, the last two pairs 

 of legs lie far behind the first two pairs, and in the female there 

 is a club-shaped organ between the first and second pairs of 

 legs on either side. 



Pediculoides is parasitic on insects, and the pregnant 

 female in the species of this genus becomes like a small 

 jigger by distension of the abdomen. In the swollen abdomen 

 the eggs hatch, and the young complete their development, 

 to issue from the mother as adults. 



Family Tyrogljpkidcs {Tvp6^ = che&se; yXi;Veji/ = to hollow 

 out); Cheese-mites (Fig. 129). Soft-bodied, light-coloured 

 mites, usually with a distinct cephalothorax ; integument 

 smooth or granulous ; chelicerai usually chelate and project- 

 ing like a rostrum ; pedipalps small ; legs of moderate length, 



