382 SYSTEM OF INSECTS. 



6. HYMENOPTERA* (Piezata R). Mr. MacLeay con- 

 siders Sirex L. as being osculant between the Order we 

 are now entering upon and the Trickoptera, and Ten- 

 thredo, L. as belonging to the latter. He appears to 

 ground this opinion chiefly upon a consideration of their 

 larvae and a slight difference in their ovipositor. As the 

 Order, as settled by Linne, has always been deemed one 

 of the most natural ones, and all the great Entomolo- 

 gists of the present sera have agreed with him in thinking 

 it so ; it seems to me that to prove them mistaken in this 

 opinion, the question should have been discussed at more 

 length, and that it requires arguments of more weight 

 than any Mr. MacLeay has at present produced to set it 

 aside. He appears in general to lay great stress upon 

 an agreement in larae and the kind of metamorphosis ; 

 and I am ready to acknowledge that it forms' a strong 

 presumption in favour of any hypothesis of affinity be- 

 tween certain tribes. But when it is had recourse to as 

 fundamental and infallible, I think it is pushed far be- 

 yond what it will bear, or is warrantable. I may be 

 wrong ; but in my apprehension, a striking agreement 

 in their general structure in the perfect state, which is 

 the acme of their nature, affords a much more satisfac- 

 tory reason for keeping two tribes together, than any 

 difference observable in their larvae or metamorphosis, 

 for separating them. Let any one compare the structure 

 of these two tribes with the Trichoptera on one side, and 

 the Hymenoptera on the other, and it will require but 

 a glance to convince him of their greater affinity to the 

 latter; and the simple inspection only of Jurine's plates 

 of the wings of Hymenoptera is calculated to produce 



3 From vpyv, a -membrane. 



