96 GOUREAU ON THE 



Besides these two species, another is found in the province 

 of Gex, the wood-cricket {Gryllus syhestris), which does not 

 appear at the same time as the field-cricket. Its larvae are 

 seen in the spring, and the perfect insect from near the end of 

 August to the beginning of winter. Some individuals would 

 appear to survive this rigorous season, as they have been found 

 under stones in the month of February. I have not observed 

 that it inhabits a burrow ; I have always found it under stones, 

 or on grass under trees at the foot of mountains. Placed in a 

 box with the female the actions of this insect resemble those 

 of the field-cricket. The male approaches the female fre- 

 quently, extends his legs, places his breast against the ground 

 and elevates the abdomen ; in this position he raises the 

 elytra and rubs them with rapidity against each other. 

 A feeble monotonous noise results very different from the 

 short, sharp sound produced by the field-cricket on a like 

 occasion. 



The wood-cricket is small, and its elytra only cover half the 

 abdomen : and what is very remarkable, the back-covers diflTer 

 in colour and consistence in the same insect: the lower or left 

 is white, soft and transparent, while the right is hard and of a 

 brown colour. Their nervures are the same in number, and 

 disposed in the same manner, but are only slightly elevated 

 on the inferior, whilst they are strong and project considerably 

 on the superior. This difference leads me to believe this 

 insect is not capable of producing sounds if it crosses its elytra 

 in any other than the natural manner, that is to say, if it places 

 the right below and the left above. The elytra of the field- 

 cricket are perfectly symmetrical, and produce a sound which- 

 ever way they are crossed. 



In the wood-cricket, the musical instrument is composed of 

 the bow, and of two sets of nervures, placed one under the 

 other, separated by another nervure, which cuts them almost at 

 a right angle. There are four nervures in the first, and six in 

 the second ; but I have not observed the brush at the origin 

 of the bow, near the transparent triangular part, which I have 

 called the treble-string in the field-cricket ; the internal border 

 of the elytron would appear to supply its place. It might be 

 that the glass, which was the only instrument I used in my 

 observations, did not magnify sufficiently to enable me to 

 distinguish parts so minute, as it was with difficulty that I could 



