264 LETTEES FEOM ALABAMA. 
middle) j the latter, into which the head is somewhat 
retractile, much resembling in shape the carapace of 
a lobster„ The upper wings or elytra are somewhat 
oval, of a smoky semi-transparent brown hue, with 
strong veins forming an irregular network. 
This insect has the faculty of producing a stri- 
dulous sound, though not of so lively a character 
as some others of its tribe. The mode in which 
this is produced is highly curious. A strong vein 
running from the base of the left elytron in the 
male insect, “ is found on the underside to be re- 
gularly notched transversely like a file. When the 
wing-covers are closed, this oblique part of the 
wing-covers lies upon the upper surface of the cor- 
responding part of the right wing-cover ; and when 
a tremulous motion is imparted to the wing-covers, 
this bar rubs against the corresponding bar of the 
right wing- cover, and thus produces a vibration, 
which is communicated to the other parts of the 
wing-covers ; which, being divided into a number 
of irregular spaces, have each a distinct vibration, 
and produce a separate sound, which unitedly forms 
the stridulation, or chirrup, so well known.”* 
This sound is confined in all cases to the male 
insect, the females wanting this peculiarity of 
structure. The true wings are capacious, triangular 
and fan-like, each folding up into a long slender 
filament, extending out behind beyond the tail. 
When unfurled they are found to be composed of 
a transparent membrane, netted with a delicate 
tracery, like the finest lace. 
Thus, as we often find in natural history, an 
object which to the incurious appears ugly, and even 
repulsive, presents on close examination so many 
* Westwood. 
