[127] 



COLLECTING AND PRESERVING INSECTS RILEY. 



Fig. 134.— The Cattle-tick. 

 Packard.) 



(After 



in habit and characters. Some of them are mere sacs, on which the 

 mouth parts or other organs are scarcely discernible. In general they 

 resemble spiders. The young, however, when they leave the egg, 

 almost invariably have but three pairs of feet, resembling in this respect 

 the Hexapods. The fourth pair is added 

 in the later stages. They are parasitic on 

 insects and other animals, and some of 

 them are vegetable feeders or live in de- 

 caying vegetable and animal matter. 



A very interesting group is comprised 

 in the family Phytoptidte or gall-making 

 mites which occur on the leaves of various 

 trees and shrubs and produce curious galls 

 or abnormal growths. These mites are 

 elongate in form, have rudimentary 



mouth-parts 

 and but four 

 legs. A com- 

 mon form:,P/iy- 

 toptus quadri- 



pes, produces a gall on the leaves of the soft 

 maple. The galls of all species should be 

 collected and pinned and also preserved in 

 alcohol, and specimens of the mites should 

 be mounted in balsam. 



The members of the genus Sarcoptes are 

 very minute and are the active source of the 

 itch in the lower animals and man. Another 

 common genus is Tyroglyphus, which in- 

 cludes the common cheese mite, T. siro. 

 Other species of this genus also sometimes 

 occur in enormous numbers in grocers' sup- 

 plies. Still others are parasitic on insects,, 

 and one species, T. phylloxerce Eiley, is very 

 beneficial, since, as its name indicates, it feeds on the Phylloxera of the 

 grapevine. 



The Ixodidse comprise the ticks which attach themselves to cattle, 

 hogs, and man, and are not at all uncommon objects. These insects 

 can be found on the animals they infest, and distinct species will be 

 found to occur on most wild mammals. The common Cattle-tick 

 BoopMlus bovis Eiley, is represented at Fig. 134. 



The family Orobatidse includes a number of small terrestrial mites, 

 which occur on the moss on trees and stones. Some species are known 

 to feed on the eggs of insects, and the one shown in the accompanying: 



Fig. 133.— a true Scorpion (Buthus 

 carolinianus). — From Packard. 



