SPINOSE EAR TICK 



365 



agree in the essential detail that the bite results in an irritating 

 lesion which is slow to heal and often leaves an ugly deep scar." 

 The tick is about two-fifths of an inch in length, irregularly oval, 

 with thick turned-up margins, roughly shagreened, and of a 

 yellowish earthy color spotted rusty red. It occurs in the Coast 

 Range mountains of California and in Mexico and according to 

 Herms is most commonly found in the dry leaves under live 

 oak trees where cattle or other animals are accustomed to lie 

 in the shade. It parses through from four to seven moults to 

 reach the adult state, occupying 

 from one to two years to com- 

 plete its life history, according 

 to its success in finding suitable 

 hosts. The bites of this tick 

 produce sharp pain, accompanied 

 by a considerable discoloration 

 around the wound, and if on an 

 arm or leg the whole limb may 

 become greatly swollen as in the 

 case of a snake bite. After scab- 

 bing over, the wound may con- 

 tinue to exude lymph and to be 

 irritable for several weeks, and it 

 is possible that infection and con- 

 sequent blood-poisoning might 

 readily occur, thus giving a basis 

 for the tales mentioned above. 



Another noteworthy member of 

 the Argasidse is the spinose ear 



tick, Otiobius (or Ornithodorus) megnini (Fig. 160), of south- 

 western United States and Mexico, and now becoming common 

 in parts of South Africa. It is very troublesome to man as well 

 as to horses and other domestic animals. The nymphs, which 

 develop from the larvae in the ears of their hosts, are peculiar in 

 having very spiny bodies, quite different from the smooth larvae 

 and adults. The nymphs remain attached to their hosts for 

 months but finally drop off to transform into adults. The 

 adults are not parasitic but lay their eggs without further feed- 

 ing. The pain and annoyance caused by the spiny nymphs in 

 the ears of domestic animals is sufficient to cause them to be- 



FIG. 160. Spiny nymph of ear 

 tick, Otiobius (or Ornithodorus) meg- 

 nini. X 10. (After Marx from 



