H Y MEN OP TERA . 



607 



tip of vein IIIi separates from the costa and coalesces with the tip of 

 vein III3 at some distance from the costa. The space thus formed 

 between the united tips of veins IIIi and III3 and the costa is termed 

 the appendicidate cell (Fig. 736, ap). 



Fig. 736.— Wings of Larra with the cells numbered: «/, appendiculate cell. 



The cells marked ;;/, m, m, in Figure 735, are termed the marginal 

 cells ; and those marked S7n, sm, sm, sm, xh.^ sttbinarginal cells. 



The following table for determining the families of the Hymen- 

 optera has been compiled from the works of several writers on this 

 order, and is merely provisional. It, however, will enable the student 

 to determine the larger and more common forms; and in the present 

 state of our knowledge the study of the minute Hymenoptera is too 

 difficult for the beginner. 



TABLE FOR DETERMINING THE FAMILIES OF THE 



HYMENOPTERA, 



A. Trochanters of the posterior legs, consisting each of two segments 

 (Fig. 737, b) ; caudal end of body in the female furnished with a 

 saw or borer for depositing the eggs. (Suborder Terebrantia.) 

 B. Abdomen joined broadly to the thorax. 

 C. Anterior tibiae with two apical spurs ; abdomen of female fur- 

 nished with a pair of saws. p. 611 Tenthredinid^. 



CC. Anterior tibise with one apical spur ; abdomen of female fur- 

 nished with a borer, p. 614 Siricid^e. 



BB. Base of abdomen constricted. 

 C. Abdomen joined to the dorsal aspect of the metathorax. p. 626. 



EVANIID^. 



CC. Insertion of the abdomen normal. 

 D. Fore wings with no closed cells.* 



* In a few Proctotrupidae the wings have one or more closed cells. 



