ENTOMOLOGY

THE BIOLOGIES AND HABITS OF TICKS 435proper occurs in southern United States and parts of )lexico whilevarieties of this species are present in tropical America, Africa, Australia,and other parts of the world. It is not only a species which produces heavylosses on account of its occurrence in tremendou numbers, but it is especiallyimportant on account of being the intermediate host of the piroplasmawhich produces Texas or splenetic fever in cattle.Our form is very restricted in host relations. It can complete developmentonly on cattle, horses, mules, and dccl', rarely on a few smaller animals.This habit has greatly facilitatcd eradication. The molts arePUTE XXYll.-The cattle tick, Boophilus anmllatus. Fig. 1 (Left)- Fully engorgedfemale. Fig. 9 (Right)- Engorged female depositing eggs. (Bishopp.)passed on the host. The females deposit from ~,500 to 4,500 eggs. Insummer these hatch in from ~o to 30 days, while in the fall and winterthe incubation period may extend to 200 days. The longevity of the seedtick varies according to temperature and humidity from about two toeight months, and the period from dropping of the engorged female tothe death of all of her progeny, or the nonparasitic period, ranges from28 days in summer to 279 days in cooler weather. The period of attachmentof the seed tick to the host until the engorged female detachesranges from 20 to 59 days. Both of these periods are of considerableimportance in connection with control by the so-called pasture rotationmethods.The Genus Rhipicephalus.- This group, though small, contains many