488 Prof. Peck on Insects which affect Oaks S^- Cherry Trees, 



At the meeting of the Board of Trustees at the seat of Gorham 

 Parsons, Esq., on the 23rd of July last, the Hon. Mr. Sullivan 

 produced several branches of oaks which contained larvae. Five 

 of these I brought home, reduced them to four or five inches in 

 length ; and in order to determine whether the larvae descended 

 into the earth, threw them into a vessel nearly filled with light 

 garden mould, covering the vessel with a piece of window-glass, 

 both to prevent the escape of the perfect insects, if any should 

 be disclosed, and to retard the drying of the mould. 



I imagined that as the larva is enclosed in the fallen branch 

 with a sufficient supply of nutriment to carry it through the feed- 

 ing state, it was intended it should enter the earth when that 

 state was passed, and that it was impelled by instinct to cut off 

 the branch, that it might be brought in safety to the ground before 

 it was quite ready to quit the wood ; but my conjecture was erro- 

 neous : there must be some other reason for this process. 



A degree of humidity is necessary to favour the development 

 of the parts of the perfect insect while it is in the nympha state ; 

 in the body and larger branches of trees the moisture is sufficient 

 for this purpose ; but in these small branches, which are killed, 

 the moisture would be exhaled by the action of the sun and wind 

 if they remained on the tree, whereas, by their falling, and being 

 thus placed nearly or quite in contact with the moist earth, their 

 humidity is preserved. It was not precisely with this view, that 

 the prepared branches were treated as above mentioned ; but the 

 purpose was attained. The vessel was kept in a warm room, the 

 wood was kept moist and one perfect insect made its appearance 

 in November, another in December ; but I believe they would 

 not have been disclosed till the spring, if the branches had re- 

 mained abroad. 



The insect belongs to a tribe composed of a number of genera 

 called Capricorn-Beetles and Wood-eaters. The genus of which 

 it is an undescribed species, is named by Fabricius, Stenocorus, 

 Linnaeus would have called it Cerambyx, It is of a dull brown 

 colour, a little brighter on the under-side, every where dotted 

 with impressed points, and sprinkled with short whitish hairs 

 •which lie close to the surface ; these give it a grayish hue under 



1 



