THE INSECTA 



155 



modified expansions of the terga of the two posterior thoracic 

 segments. 



The abdomen of the male differs in several important 

 particulars from that of the female. In both sexes there are 



Fig. 38 



Dorsal views of the female (left-hand figure) and male (right-hand 

 figure) of Periplaneta orietitalis. A, head ; e, eye ; /rw, pro- 

 notum ; jnes.n, mesonotum ; vtet.n^ metanotum ; i-io, the 

 abdominal terga, ^and g are concealed by 7 in the female, but 

 are visible, though small, in the male ; tg^ wing-covers or 

 tegmina ; lu^ rudimentary metathoracic wings of the female. 

 The well-developed metathoracic wings of the male are con- 

 cealed by the tegmina ; c, anal cerci ; st^ styles of the male. 



ten abdominal segments (not counting the podical plates), but 

 in the female several of these segments are modified, and 

 some are concealed from view. A typical segment presents 

 a broad chitinous plate, the tergum, above, and an equally 

 broad plate^ the sternum, below. The tergum and sternum 



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