532 HYMENOPTEEA. 
in their cocoons, and it is probable that birds also prey 
upon them when on the trees, both in the slug and the 
winced states. Professor Peck lias described a minute ich- 
neumon-fly, stated by Mr. Westwood to be a species of 
Eneyrtus , that stings the eggs of the slug-fly, and deposits 
in each one a single egg of her own. From this, in due 
time, a little maggot is hatched, which lives in the shell of 
the slug-fly’s egg, devours the contents, and afterwards is 
changed to a chrysalis, and then to a fly like its parent. 
Professor Peck found that great numbers of the eggs of 
the slug-fly, especially of the second hatch, were rendered 
abortive by this atom of existence. 
Ashes or quicklime, sifted on the trees by means of a 
sieve fastened to the end of a pole, was recommended, by 
the late Hon. John Lowell, of Roxbury, for the destruc- 
tion of the slugs ; and it is found to answer the purpose. 
It is probable that Mr. Haggerston’s almost universal rem- 
edy may prove to be still more effectual. 
The saw-flies, though undoubtedly belonging to the ordfcr 
Hymenoptera, depart from the general characters thereof 
more than any other insects in it. They are more dull 
and heavy in all their motions ; they have not the power- 
ful jaws of the predaceous tribes, nor the long and slender 
lower jaws and tongue of those that subsist upon honey. 
They live but a short time, and their food appears to be 
pollen, the tender parts of leaves, and sometimes the plant- 
lice and other soft-bodied insects frequenting flowers. In 
the stiffness of their upper wings, and the heaviness of 
their flight, they somewhat resemble beetles, and, analogi- 
cally, may be said to typify the Coleoptera, or, in other 
words, they may be called the beetles of the Hymenop- 
tera. They will be found, on comparison, to have some 
features in common with the crickets, which, with the ear- 
wigs, are also the representatives of the Coleoptera. Al- 
though they differ essentially from butterflies and moths, 
the resemblance of most of their young to caterpillars, hi 
