12 INSECTS INJURIOUS TO VEGETATION. 



knowji by Miss Margaretta H. Morris, of Germantown, Penn- 

 sylvania. In August, 1849, her attention was called to this 

 subject by Mr. Williamson, the principal of the Mount Airy 

 Agricultural Institute, "who discovered small gi'ubs in the 

 potato-vines on his farm, and naturally feared injurious con- 

 sequences." On the 28th of the same month and year. Miss 

 Morris sent to me some specimens of the insects in a piece of 

 the potato stalk, wherein they underwent their transformations. 

 They proved to be the beetles, described by Mr. Say under the 

 name of Baridms trinotatiis, so called from their having three 

 black dots on their backs. This kind of beetle is about three 

 twentieths of an inch long. Its body is covered with short 

 whitish haks, which give to it a gray appearance. One of 

 the black dots is on the scutel, and the others are on the hinder 

 angles of the thorax ; and, by these, it can be readily distin- 

 guished from other species. According to Miss Morris, it lays 

 its eggs singly on the plant at the base of a leaf. The grubs 

 bun-ow into and consume the inner substance of the stalk, 

 proceeding downwards towards the root. In many fields, in 

 the neighborhood of Germantown, every stem was found to 

 be infested by these insects, causing the premature decay of 

 the vines, and giving to them the appearance of having been 

 scalded. The insects undergo all their transformations in the 

 stalks. Their pupa state lasts from fourteen to twenty days, 

 and they take the beetle form during the last of August and 

 beginning of September. These insects, though common 

 enough in the Middle States, I have never found in New 

 England, in the course of thirty years of observation, and have 

 failed to discover them here since my attention was called to 

 their depredations by Miss IMorris. That they may become 

 very injurious to the potato crop where they abound, will be 

 readily admitted ; but, as they do not occur either in all places 

 here or in Europe, where the potato-rot has prevailed, they 

 cannot be justly said to produce this disease.* 

 The most pernicious of the Rhynchophorians, or snout-beetles, 



* See my communication on this insect, &c., in the New England Farmer, for 

 June 22, 1850, Vol. H. p. 204. 



