HYMENOPTERA. 381 



form, but are not quite so convex. They have a small, round, 

 yellowish head, with a black dot on each side of it, and are pro- 

 vided with twenty-two short legs. The body is green above, 

 paler at the sides, and yellowish beneath ; and it is soft, and al- 

 most transparent like jelly. The skin of the back is transversely 

 wrinkled, and covered with minute elevated points ; and there 

 are two, small, triple-pointed warts on the edge of the first ring, 

 immediately behind the head. These gelatinous and sluggish 

 creatures eat the upper surface of the leaf in large irregular patch- 

 es, leaving the veins and the skin, beneath, untouched ; and they 

 are sometimes so thick that not a leaf on the bushes is spared by 

 them, and the whole foliage looks as if it had been scorched by 

 fire, and drops off soon afterwards. They cast their skins sev- 

 eral times, leaving them extended and fastened on the leaves ; af- 

 ter the last moulting they lose their semitransparent and greenish 

 color, and acquire an opake yellowish hue. They then leave the 

 rose-bushes, some of them slowly creeping down the stem, and 

 others rolling up and dropping off, especially when the bushes 

 are shaken by the wind. Having reached the ground, they bur- 

 row to the depth of an inch or more in the earth, where each 

 one makes for itself a small oval cell, of grains of earth, cement- 

 ed with a little gummy silk. Having finished their transforma- 

 tions, and turned to flies, within their cells, they come out of the 

 ground early in August, and lay their eggs for a second brood of 

 young. These, in turn, perform their appointed work of destruc- 

 tion in the autumn ; they then go into the ground, make their 

 earthen cells, remain therein throughout the winter, and appear, 

 in the winged form, in the following spring and summer. 



During several years past, these pernicious vermin have infest- 

 ed the rose-bushes in the vicinity of Boston, and have proved so 

 injurious to them, as to have excited the attention of the Massa- 

 chusetts Horticultural Society, by whom a premium of one hun- 

 dred dollars, for the most successful mode of destroying these 

 insects, was offered, in the summer of 1840. About ten years 

 ago, I observed them in gardens in Cambridge, and then made 

 myself acquainted with their transformations. At that time they 

 had not reached Milton, my former place of residence, and have 

 appeared in that place only within two or three years. They 



