OWLET-MOTHS. 435 
the hindmost pair, and never raise the end of the body when 
at rest. Some of them make cocoons, but tbe rest go into 
the ground to transform. Many of the Noctuas vary more 
or less from the characters above given, and the tribe seems 
to admit of being divided into several smaller groups or 
families, under, which their peculiarities might be more dis- 
tinctly pointed out. Unfortunately the history of most of 
our moths is still imperfectly known ; and for this reason, as 
well as on account of the length to which tbe foregoing part 
of this treatise has already extended, I have concluded to 
suppress a considerable portion of my observations on the 
owlet-moths and the rest of the Lepidoptera , and shall con- 
fine my remarks to a few of the most injurious species in 
each of the remaining tribes. 
The injury done to vegetation by the caterpillars of the 
Noctuas, or owlet-moths, is by no means inconsiderable, and 
sometimes becomes very great and apparent; but most of 
these insects are concealed from our observation during the 
day-time, and come out from their retreats to feed only at 
night. To turn them out of their hiding-places becomes 
sometimes absolutely necessary, and it is only by dear-bought 
experience that we learn how to discover them. This is not 
the case with all ; those of the first family, which I would 
call Acronyctians (Acronyctad.-e *), live exposed on the 
leaves of trees and shrubs. They have sixteen legs, are 
cylindrical, and more or less hairy, some of them closely 
resembling those of the genus Clostera, having a wart or 
prominence on the top of the fourth and the eleventh rings, 
and some of them have the hair in tufts like Arctians and 
Liparians. They make tough silken cocoons, in texture 
almost like stiff brown paper, into which they weave the 
hairs of their bodies. Their moths have bristle-formed 
antennae, and the thorax is not crested. Their fore wings 
are generally light gray with dark spots, and in many are 
marked with a character resembling the Greek letter ijc near 
* From Acronycia, a genus of moths appearing at nightfall, as the name implies. 
