104 Biology 



introduced, in other cases the nymphs still remained attached after 

 98 days had elapsed. " After leaving the ears as nymphs) these ticks 

 usually crawl up several feet from the ground and secrete themselves in 

 cracks and crevices, where in about 7 days in September, after leaving 

 the ear, they shed a membranous skin and appear as adults without 

 spines." Fertilization then takes place and oviposition commences, after 

 which the female dies. Eggs are not laid by unfertilized females and 

 the latter may live a long time. In summer the larvae hatch out after 

 11 days. 



As far as we know the life history of megnini is unique amongst the 

 Ixodoidea since but one moult (larva to nymph) takes place upon the 

 host and the nymph stores up enough food to make it unnecessary for the 

 adult to feed before fertilization and oviposition take place. Hooker 

 believes that the adults probably never feed, and we would note that 

 this view gains support from the fact that the adult capitulum (Fig. 103) 

 is very small and that the hypostome (see p. 73) is unarmed, no similar 

 structure being known to us in other ticks. Even the structure of the 

 digit appears modified in that the external article does not bear the 

 usual outwardly directed teeth (see Fig. 104, digit of female). The 

 peculiar habit of the replete nymph of creeping upward several feet 

 from the ground before moulting appears to Hooker to be correlated 

 with the tick's parasitic habits, for when the adults mate and the 

 females oviposit, the larvae which issue from the eggs are placed in an 

 advantageous position where they can readily gain access to the ears of 

 their hosts. 



Injurious Effects: Salmon and Stiles (1901, pp. 413, 414) write: 

 "Judging from letters received by this bureau (The Bureau of Animal 

 Industry, Washington, D.C.), the ear tick is accused of causing a variety 

 of troubles. Some correspondents report sickness and even death among 

 cattle as having been caused by the parasite, while others are not 

 inclined to attach so much importance to its presence. Owing to their 

 position in the ear, it is not possible to use any very drastic measures 

 against them, but, as a rule, if any bland oil, such as linseed or olive oil, 

 is poured into the ear, the ticks will soon vacate ; they are not killed by 

 this treatment, hence every tick caught should be crushed in order to 

 prevent increase." Simpson (1901) readily removed a nymph from the 

 ear of a gentleman by introducing a pledget of cotton containing a little 

 chloroform into the ear. 



Longevity {unfed): Megnin (1885) states that he kept some 0. 

 megnini alive unfed for two years. 



