490 Prof. Peck on Insects which affect Oaks Sc Cherry Trees. 



covered and fringed with hairs ; at the base of these divisions 

 are the two labial palpi of three joints, the terminal one of the 

 same shape as in the other pair, but smaller. 



The plum-trees, Prunus domestica, have for a number of years 

 been disfigured with irregular swellings on the younger branches. 

 The seat of this disease is in the bark. The sap is diverted from 

 its regular course, and is absorbed entirely by the bark, which is 

 very much increased in thickness ; the cuticle bursts, the swelling 

 becomes irregular, and is formed into black lumps, with a cracked, 

 uneven, granulated surface. The wood, besides being deprived 

 of its nutriment, is very much compressed and the branch above 

 the tumour perishes. The cherry-tree is affected in a similar 

 manner. 



When the Board of Trustees met at the seat of John Lowell, 

 Esq. in Roxbury, on the 27th of June last, Mr. Pomroy took 

 from a cherry-tree in Mr. Lowell's garden, a small branch dis- 

 eased as above mentioned of the plum-tree. On taking off a thin 

 slice of the tumour, I found it was inhabited by living larvae ; 

 and flattered myself that the disease of both trees arose from the 

 same insect. I brought the branch home with me, and placed it 

 in a large glass phial. On the 6th of July, I perceived that the 

 larvae had left the tumour, and were uneasy in the bottom of the 

 phial. A vessel of earth was immediately prepared, as mentioned 

 above in the account of the Pruner ; the larvae when turned into 

 it buried themselves instantly. On the 30th of the same 

 month, or twenty-four days from their leaving the bark, the per- 

 fect insects began to rise. They proved to be insects which I 

 had long known to occasion the fall of peaches, apricots, and 

 plums, by the larva eating into the kernel of those fruits long 

 before they had acquired half their growth. 



This insect belongs to the same genus with the Rhynchcenus 

 Strobi or White Pine Weevil, described in the Massachusetts 

 Agricultural Journal for January 1817, to a plate in which I 

 would refer for a representation of the parts of the mouth. In 

 that, the rostrum or snout is nearly straight ; in the present 

 species it is curved, so as to form the segment of a circle. All 

 the thighs have two small obtuse points on the under side. In 



