640 EXTERNAL ANATOMY OF INSECTS. 
universally narrowest at their base and widest at the 
apex, provided we consider as the apex the termination 
outwards of the three Areas; otherwise we might say 
that wings in the Coleoptera, Orthoptera, &c., were wider 
at the base than at the apex*. The wings in the former 
Order, and in several of the Heteropterous Hemiptera, 
as Gerris, Velia, &c., may in general, as to their shape, 
be termed semicordate or semiovate>; in the Derma- 
ptera they incline to an oval figure ©; in the Strepszptera, 
Orthoptera, most Homopterous and many Heteropterous 
Hemiptera, they approach to the quadrant of a circle; 
in a considerable portion of the Lepidoptera the two 
under wings, if united at their posterior margin, approach 
a circular form; the upper ones vary a little from the 
prototype of the under ones, forming an obtusangled 
triangle 4; in many Neuroptera the primary wings may 
be called oblong or linear-oblong, while the secondary 
betray more evidently the right-angled or obtusangled 
triangle; in the Hymenoptera this latter form is every 
where conspicuous, with little deviation, except in the 
rounding of the angles *; and, finally, in the Diptera this 
form shades off again into an oblong, ovate, or linear 
shape, the wing being most commonly attenuated at the 
base into a kind of footstalk‘. Some singular variations 
with respect to the termination or marginal processes of 
the wings are exhibited by many Lepidoptera ; thus in 
Attacus Atlas, &c., the primary wings are falcated or 
hooked at their apex * ; and in great numbers both wings 
2? Prate X. Fic. 4, 5. and XXVIII. Fic. 21, 22. 
> Plate X. Fic. 4. © Tbid. Fie. 5. 
4 [bid. Fie. 6. € Ibid. Fic. 8—11. 
f Ibid. Fic. 12--15. © Pirate XIV. Fie. 4. 
A 
