ENTOMOLOGY

484 SANITARY ENTOMOLOGYstage which enters the ears. The larvre molt to nymphs within the ears infrom seven to twelve days. The nymphal stage is covered with spines,hence the common name. Engorgement in this stage requires from 81 toover 200 days. The nymphs then crawl out of the ears, hide about barns,posts, trees, etc., and molt their skins, copulate, and lay eggs, no foodbeing taken in the adult stage. The eggs are deposited in these hidingplaces and the larvae remain on the objects until brushed off by an animal.There are several other species in this genus, some of which are ofimportance as parasites of man and animals. One which is commonin the Southwest infests the burrows of prairie dogs and other wild rodentsand may attack man at nigllt. The species O. savignyi (Audouin) Kocliis widely distributed in Africa and southern Asia. It normally feeds onthe camel but often attacks man. Certain other species in the tropicsof Asia bite man, but the transmission of disease has not been definitelyconnected with them.In the family Ixodidae there are many imporr&.nt species. Only a fewwill be mentioned.The Castor Bean Tick or Black-Legged Tick, Ixodes ricinus (I,innllms).-Thisspecies is common throughout the greater part of Europeand Asia and two varieties of it occur in the United States. The mouthpartsare long, thus often producing a troublesome bite. The hostsare many, including both domestic and wild animals and man. While ithas not been connected with any disease in America, it has been clearlyshown to carry red water or bovine piroplasmosis in Europe. This tickdrops from the host to molt, the larvre engorge in from three to nine daysand molt in three to four weeks. The period of engorgement of thenymphs is practically the same as in the larvre. The nymphs require somewhatlonger to molt to adults. The females require about eight to fifteendays to become engorged, and begin depositing eggs in about two weeks.The eggs hatch in from fort." days to several months.The Genus Haemaphysalis-H. leachi (Audouin) Neumann, which iscommon in Africa, has been shown to carry malignant jaundice (Babesiacanis) of dogs. The common rabbit tick in the United States belongsto this group. Another species H. cinnabarina (Koch) punctata Canestriniand Fanzago is sometimes of importance as a parasite on catttle,sheep, and other domestic animals. All of the ticks of the group dropfor molts, and the developmental periods arc somewhat similar to thoseoutlined for Ixodes ricinus, with the exception of the species H. incrmisBirula, which occurs on deer in Europe. The immature stages of thistick engorge very rapidly, becoming replete in from IV!! to 24 hours.The Cattle Tick, Boophilus annulatus (Say) Stiles and Hassall(MargaroptUl) (plate XXVII) and Varieties of This Species.-This isprobably the most important tick in relation to live stock. B. annulatu8