80 INSECTS INJURIOUS TO VEGETATION. 



rated by the insects; and, from the burrows within, I took 

 t\velve of the blight-beetles in a living and perfect condition; 

 the thirteenth insect having previously been cut out. On the 

 ninth of July, 1844, the Hon. M. P. Wilder sent to me a piece 

 of a branch from a plum-tree, which contained, within the 

 space of one foot, four nests or branching burrows, in each of 

 which several insects in the grub and chrysalis state were 

 found, and also one that had completed its transformations. 

 Soon afterwards I caught one of the blight-beetles on a plum- 

 tree, probably about to lay her eggs. In the following month 

 of August, I received a blighted branch of an apricot-tree, one 

 inch in diameter at the largest end, and containing, within the 

 short distance of six inches, seven or eight perfect blight-beetles, 

 each in a separate burrow, and vestiges of other burrows that 

 had been destroyed in cutting the branch.* This little beetle, 

 which is only one tenth of an inch in length, was named Sco- 

 Ij/tus Pi/ri, the pear-tree Scolytus, by Professor Peck. It is of 

 a deep brown color, with the antennae and legs of the color of 

 iron-rust. The thorax is short, very convex, rounded and rough 

 before; the wing-covers are minutely punctured in rows, and 

 slope off very suddenly and obliquely behind; the shanks are 

 widened and flattened towards the end, beset with a few little 

 teeth externally, and end with a short hook; and the joints of 

 the feet are slender and entire. This insect cannot be retained 

 in the genus Scolytus, as defined by modern naturalists, but is 

 to be placed in the genus Tomicus. The minuteness of the 

 insect, the difficulty attending the discovery of the precise seat 

 of its operations before it has left the tree, and the small size 

 of the aperture through which it makes its escape from the 

 limb, are probably the reasons why it has eluded the researches 

 of those persons who disbelieve in its existence as the cause 

 of the blasting of the limbs of the pear-tree. It is to be sought 

 for at or near the lowest part of the diseased limbs, and in the 

 immediate vicinity of the buds situated about that part. The 



* See my communications on these insects in the Massachusetts Ploughman 

 for June 17, 1843. Also Downing's Horticulturist for Feb. 1848, Vol. II. p. 365^ 



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