EXTERNAL ANATOMY OF THE LOCUST. 



259 



The end of the male abdomen is blunt, ending (in our Eocky Mountain 

 species) in a turned-up, notched tip. Immediately in front of the notch 



is a convex piece or flap, 

 free anteriorly and at- 

 tached posteriorly and on 

 the sides to the ridge form- 

 ing the upper edge of the 

 10th sternite. When about 

 to unite sexually, the tip 

 of the abdomen is de- 

 pressed, the hood is drawn 

 backward, uncovering the 

 chitinous penis. (This hood 

 may be called velum jjenis.) 

 In front of the hood is the 

 supra anal plate with lat- 

 eral processes, which may 

 be called infra-anal flaps 

 (or uro-])atagia, Fig. 12, ujJ)^ 

 concealed by the cerci. At 

 I the base of the supra-anal 

 B plate, which is broad and 

 shield-shaped, and pointed 

 in front, is the fork or supra- 

 anal furcula (furciila siipra- 

 anaUs, Fig. 12,/). 



The thorax, as seen in 

 Fig. 12, consists of three 

 segments, called the pro- 

 thorax, mesothorax, and 

 metathorax, or fore, mid- 

 dle, and hind thoracic rings. 

 They each bear a pair of 

 legs, and the two hinder, 

 each a pair of wings. The 

 upper portion (tergum) of 

 the middle and hind seg- 

 ments, owing to the pres- 

 ence of wings and the neces- 

 sity of freedom of move- 

 ment to the muscles of 

 flight, are divided or dif- 

 ferentiated into two pieces, the scutum and scutellum^^ (Fig. 12), the 

 former the larger, extending across the back, and the scutellum a 



41 There are in many insects, as in many Lepidoptera and Hymenoptera and some Neuroptera, fonr 

 tergal pieces, i. e., prfescutnm, scutum, scutellum, and postscutcllum, the first and fourth pieces being 

 usually very small and often obsolete. 



