with the body, and rubs them against each other with a brisk horizontal movement. The nervures on meeting each other produce the well known sound; the areolets at the base seem to serve no other purpose than to give intensity to it. M. Burmeister, however, advances another explanation of the phenomenon in question. According to him, the air, upon being forcibly expelled from the stigmata, particularly those of the thorax, by the violent agitation which the animal imparts to its whole body, strikes against the lateral edges of the tegmina; but being unable to escape in that direction, it is forced to ascend, and comes in contact with the membranous areolets, which by being thus struck are thrown into a state of vibration. This may certainly contribute to the intensity of the sounds, but it is obvious from their nature, that they originate in a mechanical action rather than in the air issuing from the stigmata.[1]
The field cricket (A. campestris), presents a sufficient number of structural modifications, taken in connection with its mode of life, to justify the establishment of a separate genus for its reception. It is well known to reside in holes dug in the earth, where it lies in wait for insect prey. Although habitually carnivorous, it seems, however, capable of subsisting on vegetable substances; for Stoll affirms that he kept a pair alive for a considerable time by feeding them on grass and crumbs of bread. Another interesting insect of this tribe is the mole cricket (Gryllotalpa vulgaris) which has long attracted ob-
- ↑ Lacordaire's Introd. i. p. 275.
