330 Analysis of Scientific Books. 



nent character, and the insect becomes capable of propagating its 

 species. 



It appears from Rosel's account, that while very young, these 

 insects are gregarious, but not afterwards ; that they are usually 

 found in the vicinity of meadows and of fields of corn, particularly 

 of barley; to which they are very detrimental by feeding on the 

 roots, and thus intercepting the due nourishment of the plants 

 themselves. Our author has met with the mole-cricket in one 

 situation only, namely, in some peat-bogs, at the distance of a few 

 miles to the west of Oxford. In the neighbourhood of these peat- 

 bogs the insects are familiarly known by the name of croakers, 

 from the peculiar sound which they occasionally make ; a sound 

 not very unlike, but more shrill and more soft than that of the 

 frog. This sound, even in the case of a single individual, may be 

 heard at the distance of some yards ; but when made by numerous 

 individuals at the same time, it may be heard at the distance of 

 some hundred yards, provided the air be in a favourable state. 

 The insect is usually found within a foot and a half of the surface, 

 and in parts where the peat is neither quite dry, nor very moist ; 

 of such a consistence, indeed, as is most favourable to the mining 

 operations of the animal. 



The accounts of different authors differ as to the food of the 

 mole-cricket. Having kept several individuals in glass vessels 

 during some weeks, Dr. Kidd observed, that of all kinds of vege- 

 table food, they preferred the potato, while cucumber they hardly 

 touched ; but if raw meat were offered them, they attacked it with 

 great greediness, and in preference to every thing else. And, 

 when they had been kept, even but for a short time, without any 

 food, they did not hesitate to attack each other ; in which case 

 the victor soon devoured the flesh and softer parts of the van- 

 quished. ' As I have not unfrequently found them in their na- 

 tive haunts, maimed in various parts of the body, I have very little 

 doubt that, although captivity may increase their ferocity, they 

 are not, even in a natural state, free from each other's attacks. If 

 they are carnivorous, they probably feed on worms and various 

 larvae, which are abundant in the peat-bogs above-mentioned, for 

 I have repeatedly found the horny and indigestible parts of in- 

 sects within their stomachs. Similar relics I have found in the 

 stomach of the pneumora and gryllus yiridissimus. The two fol- 

 lowing facts attest, in the tribe of insects to which the mole- 

 cricket belongs, a remarkable degree of voracity, and an equally 

 remarkable power of abstaining from food. My friend Dr. Macart- 

 ney, of Dublin, informs me that he has known a gryllus devour a 

 portion of its own body: on the other hand, my friend Mr. Buck- 

 land, of this University, gave me, at the commencement of the 

 present summer, a living gryllotalpa, which had been confined 

 during nine or ten months in a tin case containing a small quan- 



