INSECT ABDOMEN SNODGRASS 



8s 



The ovipositor of Anasa tristis is small, and is ordinarily concealed 

 beneath the large first valvifers (fig. 27 B, iVlf). When the valvifers 

 are spread apart, however, the lobes of the ovipositor are exposed 

 (D), and between the bases of the first pair is seen the large, open 

 genital chamber (GC), into which the oviduct discharges anteriorly. 

 The ovipositor has the typical hemipterous structure, except that the 

 first valvifers are relatively very large, and the third valvulae are ab- 



vniv 



Fig. 27. — Abdomen and ovipositor of Anasa Iristis (Coreidae). 



A, entire abdomen, dorsal view. 



B, same, ventral view. 



C, lateral view of genital segments, with left wall of segment I'll removed. 



D, ventral view of genital region, with valvifers (iVlf) spread apart, show- 

 ing lobes of ovipositor (iVl, 2VI), and large genital chamber (GC) opening 

 between anterior pair. 



E, left side of ovipositor and ninth tergum, with first valvifers removed, show- 

 ing basal union of first valvula {iVl) with arm (w) of ninth tergum. 



sent. The four lobes associated with the opening of the genital chamber 

 are the first and second valvulae (D, iVl, 2VI). 



The first valvifers, as we have seen, are large triangular plates lying 

 like a pair of valves (fig. 27 B, iVlf) beneath the lobes of the ovi- 

 positor. Their bases are attached to the membrane behind the seventh 

 segment (C) ventral to the eighth tergum. On the anterior margin 

 of each valvifer is a strong apodeme for muscle attachments. The 

 venter of the eighth segment is entirely membranous, and is repre- 



