166 TRANSFORMATIONS OF INSECTS. 
The principal divisions of the //ymenoptera are readily dis- 
tinguished by characteristic species, so that their classification 
is comparatively simple, and some remarkable habits which are 
prevalent amongst some peculiarly constructed kinds appear to 
have definite relations with their metamorphosis. 
THE. HYMENOPTERA WITH OV IPOSITORS. 
(Zenthredinide and Siricid@.) 
The celebrated entomologist Latreille distinguished the y- 
menoptera which had the abdomen attached to the rest of the 
body by its entire width from those which had a slender, waist- 
like junction. This distinction, although not very important, is 
THE OVIPOSITOR OF THE Hylotoma rosea. 
very handy. The species with thick waists are collected into two 
families, one very numerous in species and the other much less 
so. The principal, or first family, is that of the saw-flies, or 
Tenthredinide, and the other the Szviczde. 
The saw-flies are common everywhere, and are to be seen 
and watched whilst they fly, work, and crawl about in nearly 
every garden and wood. Once seen, the peculiar habits and 
odd manners of these active flies are never forgotten. Their 
body is short and compact, their mandibles are long, flat, and 
cutting, the jaws are short, feeble, and furnished with six-jointed 
palpi, and the antenne are either thread-shaped or are thick 
at the end or branched. The Tenxthredinide are particularly 
