OF THE HIND WINGS OF HYMENOPTEROUS INSECTS. 137 



I have examined this apparatus in different genera of Lepidoptera. The bristle is 

 usually not only double or divided and forked from the base, instead of single, but also is 

 much weaker in the females than iu the males. 



It has no affinity in its structure with the hooks on the hind Avings of Hymenoptera and 

 Aphides here described ; and from its situation at the base of the wing, its flexible and 

 elastic character, and from the imperfection of the loop, it can have little effect in keeping the 

 wings "in the same line during Hight," or at least an effect very diGferent from that produced 

 by the hooks on the margin of the wings of Hymenoptera and Aphides, which, wherever 

 they may commence, always reach to near the middle of the wing, and are thus able to act 

 with considerable power in connecting the two wings and keeping them in place. 



I cannot believe that the use of this apparatus in the Lepidoptera has yet been disco- 

 vered, or that it is of the same nature with that of the hooks here described. Perhaps 

 the name of " spriag," which Mr. Haworth gives to it, may best illustrate its use. 



EXPLANATION OP THE PLATES. 



Tab. 16. 



Hind Wings of Hymenoptera Terebrantia, Latr., and Aphis. 



1. Allantus (N. America), a. the 16 distal hooks and the first sub-basal. 



2. Cephus pygmxus. 

 Hylotoma, A. a. the distal hooks, 



, B. The distal hooks. 



ustulata. Distal hooks, and, i and 2. ? sub-basal hooks. 



femoralis. a. tip of wing. 



Pe7-ffa. 



Pterygophorus. a. base of wing : b. i, lo. distal hooks ; i, s. sub-basal hooks. 



Tenthredo viridis. a. the distal and three first sub-basal hooks ; i, 2, 3. end of nerve. 



Tenthredo, sp. n. ? i, 2, 3. end of nerves. 



Sciapteryx costalis. a. end of costal nerve. 



Fig. 12. Xyphidria Dromedarius. a. sub-basal hooks. 



Fig. 13. Sir ex Juvencus. 



Fig. 13 a. Wing of Aphis hieracii. 



Fig. 14. Cryptus, Europe. 



Fig. 15. Cri/^^M«, England. Scar of sub-basal hook. 



Fig. 16. Mesostenus. 



Fig. 17. Ophion obscurus. a. the distal hooks ; b. sub-basal hooks. 



Fig. 18. combustus. sub-basal hooks. 



Fig. 19. Paniscus (England), a. sub-basal hooks. 

 Fig. 20. Pimpla, England. 



Fig. 21. , N. America, distal hooks. 



Fig. 22. Osprynchotus. a. base of costal nerve. 



Fig. 23. Tragus. 



Fig. 24. Chalcis. a. distal hooks. 



Fig. 25. Chrysis. a. the sub-basal hooks. 



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