98 INSECTS INJURIOUS TO VEGETATION. 



inches, in sinuous channels, or penetrate the solid wood an 

 equal distance. It is supposed that three years are required 

 to mature the insect. Various expedients have been tried to 

 arrest their course, but without effect. A stream, thrown into 

 the tops of the trees from the hydrant, is often used with good 

 success to dislodge other insects ; but the borer-beetles, when 

 thus disturbed, take wing and hover over the trees till all is 

 quiet, and then alight and go to work again. The trunks and 

 branches of some of the trees have been washed over with 

 various preparations without benefit. Boring the trunk near the 

 ground, and putting in sulphur and other drugs, and plugging, 

 have been tried with as little effect." 



This beetle I have taken in Massachusetts only in June, 

 mostly between the first and seventeenth, and none after the 

 twentieth day of the month. The grub closely resembles that 

 of the apple-tree borer. Figures of the insect, in all its stages, 

 may be seen in the tenth volume of Hovey's Magazine, page 

 330. 



There is another destructive Sapo'da, whose history remains 

 to be written. It is the Saperda tridentata, so named by 

 Olivier on account of the tridentate or three-toothed red bor- 

 der of its wing-covers. This beetle is of a dark brown color, 

 with a tint of gi*ay, owing to a thin coating of very short down. 

 It is ornamented with a curved line behind the eyes, two stripes 

 on the thorax, and a three-toothed or three-branched stripe on 

 the outer edge of each wing-cover, of a rusty red color. There 

 are also six black dots on the thorax, two above, and two on 

 the sides; and each of the angles between the branches and 

 the lateral stripes of the w^ing-covers is marked with a blackish 

 spot. The two hinder branches are oblique, and extend nearly 

 or quite to the suture ; the anterior branch is short and hooked. 

 Its average length is about half an inch; but it varies from 

 four to six tenths of an inch. The males are smaller than the 

 females, but have longer antennae. This pretty beetle has 

 been long known to me, but its habits were not ascertained 

 till the year 1847. On the nineteenth of June, in that year, 

 Theophilus Parsons, Esq., sent to me some fragments of bark 

 and insects which were taken by Mr. J. Richardson from the 



