ACAEINA. 



491 



in tufts from a pair of stigmata, placed, as a rule, before or behind 

 the last pair of legs (fig. 380, St). 



The common generative opening is placed as a rule far away from 

 the anus, and may be situated anteriorly between the last pair of 

 legs (fig. 381, a, b). There may be a special copulatory opening, as in 



' 



FIG. 381. a, Male; b, female genital organs of A rgat (after A1. ragenstecher). T, Testes ; 

 Vd, seminal duct ; Dr, prostate gland ; Go, genital opening ; Ov, ovaries ; Od, oviduct ; 

 U, uterus ; Dr, glandular appendages. 



the itch-mites (Sarcoptidce), through which the sperm passes into the 

 receptaculum. The males are often distinguished not only by their 



b 



Kt 



a 



I), 



li 



FIG. cS2. Lnrva of a IIydracl.ua. 6, Its pupn. Ef, cbeiicera; JL'f, podipalpus ; Oc, eyes; 



S, legs. 



appendages, which are more powerful and of a slightly different 

 form, but also by the possession of posterior suctorial pits, 

 and sometimes also by the manner of nourishment and mode 

 of life. The Acarina are, with the exception of the viviparous 



