Def. Metamorphosis obtected[1223].
Mouth antliate[1224].
Prothorax very short, covered by a pair of tippets.
Wings four, covered partially or generally with minute scales: neuration branching, often with a central areolet.
10. Diptera[1225] (Antliata F.). This Order likewise appears indebted for its name to the philosopher of Stagyra, who distinguishes the members of it from their counter-parts—the Hymenoptera—by their having an oral, while these have an anal sting[1226]: and we may add, that while the last, on account of their wonderful economy and the benefits which by them Providence confers upon mankind, have been justly regarded as the princes of the winged insect world,—the former, when we consider the filthy and disgusting habits of their grubs, and the annoyance, both from their numbers and incessant assaults, of them, in their fly-state, may very properly be considered as its canaille. Almost all the tribes of Hymenoptera, from the saw-flies to the ants, have their representatives in this Order. Though the number of wings is its prominent feature, yet there are two-winged insects in other Orders, as some Ephemeræ: and the Eproboscidea of Latreille seem rather a kind of winged Aptera, if we consider their trophi, than real Diptera; or they may form an osculant group, partly winged and partly apterous, between the two. I have before remarked, that though, apparently, the insects of this Order have only two wings, yet the under or secondary wings of the other Orders have in them their representative[1227]. Their poisers also, I formerly observed to you, are probably more connected with their respiration than with their flight[1228].
Def. Metamorphosis incomplete, or coarctate.
Mouth proboscidate[1229].
Prothorax replaced by a collar. Sutures of the trunk mostly spurious[1230].
Wings two, with winglets attached to them: neuration various[1231]. Poisers.
Tarsi pentamerous.