631 



3. Legs short, without clavate hair on tarsi I and II ; living on 



insects ..*,,. ... Canestrininae. 



Legs longer, with clavate hair on tarsi I and II ; not parasitic 

 except on bees . . "' ; " . . . . . Tyroglyphinae. 



4. Possessing some specially developed apparatus for clinging to 



the hairs of mammals . ... . , . . Listrophorinae. 



Without such apparatus . ... . . . . . . . . 5 



5. Living on the plumage of birds . . ' '. . . . Analgesinae. 

 Not on plumage of birds, but in living tissues ...... 6 



6. Vulva longitudinal ; in skin and cellular tissues of birds . . Cytoleichinae. 

 Vulva transverse ; in skin of mammals and birds . . . Sarcoptinae. 



Only three of these, the Tarsoneminae, the Tyroglyphinae and the 

 Sarcoptinae, which contain the itch mites, concern us here. 



SUBFAMILY TARSONEMINAE 



Soft bodied mites which resemble the Tyroglyphinae, the female differ- 

 ing in having a club-shaped organ between legs I and II. Palpi minute 

 and the mandibles slender and needle-like. The posterior pairs of legs 

 are widely separated from the anterior. Legs short and composed of five 

 or six segments; the anterior tarsi have one claw, the others two. Tracheae 

 present, opening on the ventral surface near the base of the rostrum. 



This subfamily contains the genus Pediculoides, in which all the legs 

 of the female end in claws and suckers. P. ventricosus is a common 

 pest among those who handle cereals, and sometimes causes a cutaneous 

 eruption. 



SUBFAMILY TYROGLYPHINAE 



Pale-coloured mites with soft bodies twice as long as broad and broadest 

 just behind the middle. Mandibles chelate; palpi small. Legs long, ending 

 in a single claw; the hair at the end of the penultimate segment of legs I 

 and II is very long ; a clavate hair near the bases of tarsi of legs I and II. 

 Eyes and spiracles wanting. Genital orifice elongate and situated 

 between the hind coxae. 



The mites belonging to this family feed chiefly on vegetable matter, 

 a few on animal substance as well ; they are commonly found in 

 cereals of all kinds, and in other products such as cheese, flour, ham, and 

 dried meats ; they often attack entomological specimens. A number of 

 these mites have been known to attack man and to cause serious skin 

 eruptions ; Gedoelst gives the species which do so in his Synopsis de 

 Parasitologie. 



The life history of some of the tyroglyphid mites is very remarkable. 

 Except for the species of one genus, which are viviparous, all lay eggs. 



