16 MONTANA EXPERIMENT STATION BULLETIN 408 



South of the United States the species is known from Mexico, Cen- 

 tral and South America, as well as other parts of the world. 



The first Montana record of the spinose ear tick was based on 

 specimens collected near Park City in February, 1916, under con- 

 ditions which indicated that it had been present for several years. 

 This was reported in the Fourteenth Report of the State Entomol- 

 ogist, Montana Agricultural Experiment Station Bulletin 112, page 

 67 (1916). As many as 109 ticks were taken from the ears of one 

 calf at that time. Apparently the infestation disappeared, for this 

 pest was not again reported until the spring of 1941, when speci- 

 mens were submitted by Dr. W. J. Butler, State Veterinarian, which 

 were collected from the ears of Mexican cattle that had been 

 shipped into the upper Yellowstone Valley. Since then several 

 lots of specimens have been examined. 



The spinose ear tick is known to attack cattle, horses, sheep, 

 cats, and occasionally man. Its life history, as it is known, is as 

 follows: the newly-hatched, tiny, six-legged seed ticks enter the 

 ears of the animals attacked and attach themselves well below the 

 hair line. In a week or two they become engorged and shed their 

 skins, becoming eight-legged nymphs which bear little resemblance 

 to the first stage. These nymphs are covered with small spines, and 

 are constricted somewhat across the middle (see cover illustration). 

 Ticks in this stage remain in the ears for from one to seven months 

 when they drop to the ground, crawl into dry, protected places, and 

 shed their skins a second time. This moult produces the adults, 

 which are spineless and somewhat flattened. It is not believed 

 that the adults attach to any animal or take food of any kind. 

 Mating and egg laying then take place and under favorable condi- 

 tions the eggs may hatch in 10 days. Soon after, the little ticks 

 are ready to attach to any of their hosts, settle down in the ears, 

 and continue the life cycle. They may live for three months if 

 no host is found. 



The factors which limit the spread or continued development 

 of this pest are unknown, but judging from previous experience, 

 and in spite of the lack of specimens received in 1942, it might 

 remain for some time before it disappears. 



A few ticks in the ears of an animal probably do little dam- 

 age. However, when gross infestations exist considerable injury 

 may occur. The ticks and ear secretions may completely plug the 

 opening and some of them may move as far in as the ear drum. 

 The infested animal usually snakes its head and moves it from 

 side to side. There is a tendency to rub or scratch the ears when 

 the irritation is intense, and young animals often run as if at- 

 tempting to relieve the nervous tension. Infested animals do not 

 do well. Some of them lose flesh and, rarely, the calves may die. 



Because of the point of attachment of the ticks, ordinary dip- 

 ping will not remove them. A mixture of 2 parts of pine tar to 



