434 SANITARY ENTOMOLOGY 



stage which enters the ears. The larva molt to nymphs within the ears in 

 from seven to twelve days. The nymphal stage is covered with spines, 

 hence the common name. Engorgement in this stage requires from 31 to 

 over 200 days. The nymphs then crawl out of the ears, hide about bams, 

 posts, trees, etc., and molt their skins, copulate, and lay eggs, no food 

 being taken in the adult stage. The eggs are deposited in these hiding 

 places 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 of 

 importance as parasites of man and animals. One which is common 

 in the Southwest infests the burrows of prairie dogs and other wild rodents 

 and may attack man at night. The species f). savignyi (Audouin) Koch 

 is widely distributed in Africa and southern Asia. It normally feeds on 

 the camel but often attacks man. Certain other species in the tropics 

 of Asia bite man, but the transmission of disease has not been definitely 

 connected with them. 



In the family Ixodidae there are many important species. Only a few 

 will be mentioned. 



The Castor Bean Tick or Black-Legged Tick, Ixodes ricvnus (Lin- 

 nseus). — This species is common throughout the greater part of Europe 

 and Asia and two varieties of it occur in the United States. The mouth- 

 parts are long, thus often producing a troublesome bite. The hosts 

 are many, including both domestic and wild animals and man. While it 

 has not been connected with any disease in America, it has been clearly 

 shown to carry red water or bovine piroplasmosis in Europe. This tick 

 drops from the host to molt, the larvse engorge in from three to nine days 

 and molt in three to four weeks. The period of engorgement of the 

 nymphs is practically the same as in the larvse. The nymphs require some- 

 what longer to molt to adults. The females require about eight to fifteen 

 days to become engorged, and begin depositing eggs in about two weeks. 

 The eggs hatch in from forty days to several months. 



The GeTj^s Haemaphysalis — H. leachi (Audouin) Neumann, which is 

 common in Africa, has been shown to carry malignant jaundice (Babesia 

 canis) of dogs. The common rabbit tick in the United States belongs 

 to this group. Another species H. cinnabarina (Koch) puncta'ta Canes- 

 trini and Fanzago is sometimes of importance as a parasite on catttle, 

 sheep, and other domestic animals. All of the ticks of the group drop 

 for molts, and the developmental periods are somewhat similar to those 

 outlined for Ixodes ricinus, with the exception of the species H. inermis 

 Birula, which occurs on deer in Europe. The immature stages of this 

 tick engorge very rapidly, becoming replete in from IV2 to 24 hours. 



The Cattle Tick, BoopMlus amiulatus (Say) Stiles and Hassall 

 (Margaropurs) (plate XXVII) and Varieties of This Species. — This is 

 probably the most important tick in relation to live stock. B. annulatus 



