OF THE HIND WINGS OF HYMENOPTEROUS INSECTS. 



129 



Chalcidid^. 

 Chalcis, fig. 24 



One vein only, simple ; ceasing at centre of wing 

 end of vein. 



Distal hooks on 



III. Costal nerve not divided at the base ; marginal ; joined about the centre hy the nerve 



below. 

 A. The two nerves continued after the junction as one, no longer marginal. Distal 

 hooks commencing before the junction on costal nerve. 



XyPHIDRIIDyE. 



Xyphidria, fig. 12. . . . 

 Tenthredinid.e. 



Perga, fig. 7 



Pterygophorus (2 species), fig. 8. 



Urocerid^. 



Sir ex, fig. 13 



Row of hooks single. 



^ 



y Tip of wing as in Tenthredo, &c. below. 



J 



The costal nerve is divided at the base — the lower branch bent 

 down and ceasing, whilst the upper is continued and joined hj 

 the nerve below,and the two become one nerve nolonger marginal. 



Costal nerve and nerve below both reaching nearlj- to the margin 

 at the tip of the wing without meeting there. 



N.B. All the other characters of Pterygophorus corresponding with 

 this section, I have placed it here, notwithstanding the division in 

 the costal nerve, this division being totally unlike that in sec- 

 tion I., and, indeed, as far as I have observed, being peculiar to 

 Pterygophorus. 



Row of hooks double. 



, Costal nerve and nerve below not joining at the tip. 



B, A loop formed at the junction of the nerves, by their separation and re-junction. 

 The two nerves continued after the re-junction as one, no longer marginal. Distal 

 hooks commencing before the junction on costal nerve. 



Row of hooks double. 

 Tenthredinid^ Tip of wing: the costal nerve and nerve below join, and one is 



continued for a short distance ; never quite to the margin. 

 Tenthredo (3 species), figs. 9, 10. 

 Allantus (2 species), fig. 1. 

 Ahia. 



Sciapteryx, fig. 1 1 . 

 Hylotoma (7 species), figs. 3 to 6. In some of the Hylotomce the costal nerve is interrupted, rendering 



the loop exceedingly indistinct ; sometimes it is even lost, but 



there is always an indication of it. 



I now proceed to describe the two groups of hooks found on the wings. 



TJie Distal hooks are present on all the hind wings of Hymenopterous insects that I 

 have examined. 



In the IcHNEUMONiD^ they are long and rc-curved (sometimes losing the re-curve 

 towards the tip of the wing), and are situated on the lower division of the costal nerve 



VOL. XXIII. s 



