237 



kept alive for nine or ten months in garden mould without the pos- 

 sibility of obtaining any other nourishment than such as it might 

 contain. 



Having noticed the general habitudes and characters of the in- 

 sect, Dr. Kidd proceeds to describe its separate parts, and enumerates 

 the peculiarities of the head, thorax, and abdomen. The digestive 

 organs, he observes, more closely resemble those of a graminivorous 

 bird than of any other animal -, the oesophagus terminating in a large 

 oval crop, communicating by a muscular tube with the gizzard, which 

 is nearly spherical, and has a thick external muscular coat lined by a 

 glandular membrane, the inner surface of which is divided longitu- 

 dinally into six equal parts, each furnished with three series of ser- 

 rated teeth of the hardness of tortoiseshell, and amounting in all 

 to 270. 



In his description of the organs of respiration of the Gryllotalpa, 

 D. Kidd states, that ten stigmata are distinctly visible on each side 

 of the body. The first of these, situated near the lower part of the 

 posterior ridge of the thorax, is not like the others a mere dot or 

 point, but an elongated fissure, apparently connected with all the 

 tracheae both of the thorax and head. To demonstrate the distribu- 

 tion of the tracheae, the insect was dried in an exhausted receiver, 

 containing muriate of lime, a method applicable to many delicate 

 anatomical preparations ; they penetrate every part of the body, and 

 are possibly, in the author's opinion, the instruments of sanguineous 

 circulation in insects, absorbing the blood in the first instance from the 

 internal surface of the alimentary canal, and thence conveying it over 

 the body. No difficulty, he apprehends, attaches to the supposition 

 that such an absorption may take place, seeing that innumerable mi- 

 nute ramifications of the tracheae penetrate the intestinal canal to 

 every part. If, he continues, it should be urged that the tracheae are 

 not found charged with blood after the death of the animal, it may 

 be answered, that the arteries are found empty after death in the 

 higher orders of animals. He adds, that he has seen some of the 

 ramifications of those tracheae which are connected with the caeca, 

 distended with a fluid of the same colour as that found in those or- 

 gans ; and though he has only witnessed this in two instances, yet 

 such a fact even singly taken, must be allowed to be of considerable 

 importance. 



The author then adverts to the objections which may be urged 

 against the hypothesis of the transudation of chyle through the coats 

 of the intestines, trusting that his opinion of a sanguineous circula- 

 tion in insects will not be hastily rejected ; and concludes his paper 

 with a description of the nerves and of the sexual organs of the in- 

 sect ; and with some remarks upon the organ of sound, which he con- 

 siders as produced by the wings, and in no way connected with a 

 peculiar tense membrane, situated between the fourth and fifth stigma 

 on each side -of the abdomen. 



