BIONOMICS OF ARGAS PERSICUS 583 



behind it and extending up towards the coxal fold. Genital opening not 

 conspicuous. All coxae contiguous. Capitulum with a moderately 

 broad base and two distinct hairs on ventral surface at base of hypostome. 

 Female very similar to the male, but readily distinguished from it by the 

 more rounded anterior end and by the large size of the genital opening. 

 Male length 4'2 to 4*8 mm. ; width 4*5 to 5 mm. Female, length 

 5 to 5'5 mm. ; width 5 mm. 



The life histories of the ticks of the genus Argas are best exemplified 

 by that of Argas Persians, which has been carefully studied by Lounsbury. 

 The eggs are laid in cracks and crevices in the wood- 

 work of the fowl coop, or other places where the ticks "" onomic8 a " d life 

 UM . in. t k- u i i -J history or Argas 



hide. Iney are or a shiny brown colour and are laid persicus 



in batches of from 20 to 100. The larvae (Plate 

 LXXV, fig. 1) hatch out in three weeks or more, according to the 

 temperature ; they are ready to feed on about the fourth day after 

 hatching and as a rule attach themselves under the wings, though they 

 may be seen on other parts ; they become replete by about the fifth day 

 after attachment. Just prior to leaving the fowl, the body of the larva 

 elongates and flattens, and it is then exactly like a miniature adult. This 

 change appears to be a special adaptation to the environment of the 

 tick, as when it is flat it can more easily pass into narrow cracks, 

 which it at once seeks on dropping from the fowl. It now slowly digests 

 the blood, and after a short interval sheds its skin and the first nymphal 

 instar emerges ; it is distinguished from the larva by having eight legs 

 and a pair of spiracles. After a few days it is ready to feed, and this 

 time it only takes from one to two hours to fill itself with blood ; it drops 

 off and again crawls into a crevice, where it develops further, emerging 

 after about two weeks as the second nymphal instar. It again goes 

 through the same process and finally, after a period of about two weeks, 

 becomes an adult male or female. The male is smaller and only partially 

 fills itself with blood and may be mistaken for the second nymphal stage ; 

 the presence of the genital opening, which is absent in the nymph will, 

 however, suffice to distinguish it. The adults feed about once a month, 

 the female returning after each meal to lay a batch of eggs ; during the 

 cold weather the intervals between the feeds are much prolonged. All 

 stages of persicus, like most others of the Argatini, can live long periods 

 without food. 



The variety miniatus, Koch, C. L., which is widely distributed in 

 the United States (Western Texas, Arizona, Florida, Iowa, California), 

 where it is known as the ' blue bug ', or ' tampan ', attacks chickens, 



