THE ACiilDIDAE OF ILLINOIS. 
Acrididae is the name of a family of insects belonging to the 
order Orthoptera. This order, as stated in my first report, is dis¬ 
tinguished from the other orders of insects by the following character¬ 
istics: 
The upper wings are leathery, or parchment like, one overlapping 
the other more or less at the base and not meeting in a straight sut¬ 
ure along the back as do the upper wings of beetles (except in the 
Forficulidce)] under wings thin and membranous, folding lengthwise 
like a fan; transformations incomplete, that is to say, there is no true 
chrysalis state as in the case of beetles and butterflies, but from the 
first they have the form of the full-grown insect, only differing in 
size and absence of wings; they undergo moults, but have no quiet, 
resting pupa stage in which feeding is suspended, but continue to eat 
from first to last with equal vigor, except during the short time they 
are undergoing their moults. 
The order embraces a large number of species which differ much in 
appearance and characters, and are generally known in this country 
by the common names Earwigs, Cockroaches, Devil’s-horses, Walking- 
sticks, Grasshoppers, Katy-dids and Crickets. 
Each of these names represents a distinct family of the order, thus: 
Earwigs—the family. Forficulidae. 
Cockroaches—the family. Blattidae. 
Devil’s-horses—the family. Mantidae. 
Walking-sticks—the family. Phasmidae. 
Grasshoppers—the family. Acrididae. 
Katy-dids—the family. Locustidae. 
Crickets—the family. Gryllidae. * 
Other insects and other families are included in the order by some 
entomologists, but there appears to be a general agreement that those 
mentioned here are properly embraced in it; besides these are all that 
can be included under the definition or characteristics given. 
One difficulty experienced in attempting to convey to the general 
readers, who have devoted no special attention to entomology, correct 
ideas in reference to the species and groups of this order, is the fact 
that the popular names are so variously applied that they" cannot be 
used without special explanation. For example, a true Earwig is an 
insect resembling a slender flattened beetle with short wing-cases; 
whereas the name is often applied, at least in parts of our state, to 
certain elongate, slender, many-legged centipedes found under stones, 
bark, etc., especially to the species of Geophilidce. The name “Devil’s 
Horse” is not uniformly applied to the Mantis, but often to our Phas- 
mae, or “Walking-sticks.” The common name “grasshopper” has like¬ 
wise been unfortunate in its use and application, not only in a popu- 
