74 



ADULT FEMALE. 



becomes separated. Not very widely separated from 

 the rostrum are the two pairs of spiracles which are 

 frequently accompanied by grouped glands (" para- 

 stigmatic glands," Green). The free abdominal seg- 

 ments vary in number and character from a rounded 

 to a tuberculate form, and frequently bear a number 

 of dorsal tubular spinnerets, and occasionally a few 

 spines. 



The pygidium (Fig. 11), which consists of several 

 segments fused together, is a flat chitinised organ 



dorsal 



1 



u 



dd 



d 



FIG. 11. Pygidium of Mytilaspis pomorum, $, X 250; showing dorsal 

 and ventral parts : a, anal opening ; b, dorsal tabular spinnerets ; 

 c, marginal tubular spinnerets with their more or less projecting 

 pores; d, median, second, and third pairs of lobes; e, plates; /, 

 spines ; g, vaginal opening ; h, anterior, anterior lateral, and 

 posterior lateral grouped circumgenital glands. 



affording the salient characters- for the separation of 

 the species. On the dorsal surface of the pygidium is 

 placed the anal opening (Fig. 11, a), and usually a 

 varying number of secreting pores with connecting 



