364 ECONOMIC ENTOMOLOGY 



sprinkling Paris green on the floor of greenhouses and covering it with 

 damp boards; trapping by means of inverted flower pots containing 

 damp hay or moss; flushing crevices, edges of greenhouse beds, benches 

 and ground beneath with hot water or steam; fumigation with NaCN 

 or KCN {}i-y2 oz. of cyanide to every 100 cubic feet of space). 



Class Arachnida 



ORDER ACARINA (MITES AND TICKS) 



Abdomen unsegmented, sometimes with annulations; without a 

 deep constriction between cephalo thorax and abdomen; legs usually 

 well developed; body more or less depressed. 



Chief Families and Genera 



EriophyidcB = Elongated annulated forms. Eriophyes — on plants. 



ArgasidcR — Argus, Ornilhodoros — on birds and mammals. 



Ixodidce = Ixodes, Dermacentor , Rhipicenlor, Mar gar opus, Boophiltis, Amblyomnta 



— on mammals. 

 Dermanyssidce = Liponyssus, Dermanyssus — chiefly on birds. 

 GamasidcE = Lcclaps — on Arthropods and mammals. 



Tarsonemidce = Pediculoides, Tarsonemus — on man and grain and other plants. 

 TyroglyphidcE = Tyroglyphus, Rhizoglyphus — on dried fruits and bulbs, and man. 

 Sarcoptida = Psoroples, Sarcoptes, Chorioptes — producing itch on mammals and 



birds. 

 Telranychida = Tetranychus, Bryobia — on plants. 

 Trombidiida — Trombidium. Harvest mites. 



(Consult Handbook of Medical Entomology, hy Riley and Johannsen, pp. 259- 

 273). 



Family Dermanyssid^ (Poultry Mites) 



(Consult Bulls. 553 and 801, Bur. Ent., U. S. Dep. Agric.) 



A most common form is the Chicken Mite {Dermanyssus gallitice 

 DeG.), a flattened, elliptical mite, with 8 legs, }^q inch long, distinctly 

 reddish after feeding. 



The eggs are oval, smooth and pearly white, and laid in cracks and 

 crevices of the wood or straw of the nests and roosts. They hatch 

 in 48 hours at summer temperature and young mites become mature 

 in less than 10 days. They are most active at night. The young 

 larva on hatching is white and has 3 pairs of legs. In about 24 hours 



