OF THE HIND WINGS OF HYMENOPTEROUS INSECTS. 129 
CHALCIDID.E. 
Chalets, fig. 24 . . . One vein only, simple ; ceasing at centre of wing. Distal hooks on 
end of vein. 
III. Costal nerve not divided at the base; marginal; joined about the centre by 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. 
Xyphidriid^e. 
Xyphidria, fig. 12 
Row of hooks single. 
Tenthredinid*:. ? Tip ° fwinff aS in Tenihredo , &c. below. 
Perga, fig. 7 
Pterygophorus (2 species), fig. 8. The costal nerve is divided at the base — the lower branch bent 
down and ceasing, whilst the upper is continued and joined by 
the nerve below,and the two become one nerve no longer marginal. 
Costal nerve and nerve below both reaching nearly 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. 
Urocerid^. 
Row of hooks double. 
Sirex, fig. 13 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. 
>f 
if 
continued for a short distance; never quite to the margin. 
Tenthredo (3 species), figs. 9, 10. 
Allantns (2 species), fig. 1. 
Abia. 
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. 
The Distal hooks are present on aU the hind wings of Hymenopterous insects that I 
have examined. 
In the IcHNEUMONiDiE they are long and re-curved (sometimes losing the re-curve 
towards the tip of the wing), and are situated on the lower division of the costal nerve 
v ol. xxiii 
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