304 



festoons are more marked in males, and the male often 

 has tarsal spurs when they are absent in the female. 



(3) The females, on the other hand, may have 

 porose areas, structures not found in the larva, nymph, 

 or male (Figs. 95 and 96). The females alone become 

 gorged in the manner so characteristic of the Ixodinae. 



ARGASINAE 



The head rises from the ventral surface, and the 

 animal is completely devoid of any scutum. The 

 stigmata are situated between the third and fourth 

 legs. The limbs, even in fully-grown and gorged 

 animals, are large and strong in proportion to the body. 



The pulvilli of the tarsi are absent in the adult. 

 The palpi are free, short, filiform, and consist of four 

 segments. The eyes are absent in Argas, and may be 

 present or absent in Ornithodoros. There is a hood-like 

 fold (the camerostome) in Ornithodoros - , lying in front 

 of and around the base of the head (Fig. 100). This is 

 not present in Argas. The abdomen does not become 

 hypertrophied during feeding, as in most of the 

 Ixodinae, out of all proportion to the head and limbs, 

 and growth takes place uniformly ; the fully developed 

 animals being identical, in all except size, with the 

 smallest forms. 



DISTINCTION OF SEXES 



The males are with difficulty distinguishable from 

 the females. In the male the genital opening is 

 narrow and semilu-nar, nearly as long as broad. In the 

 female the opening is an elongated slit with parallel 

 lips, about as broad as the rostrum. 



