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Nothing emerged until the following spring, except a single para- 

 site taken September 14. On the 9th April, hving larvcie of Saperda 

 were found still withm the wood, but no imagos had appeared in 

 the boxes, neither were any pupae discovered. On the 17th of that 

 month, both larvirie and pupae were detected, and on the 2d of May, 

 the first imagos appeared, three in number. On the third another 

 imago emerged, on the 5th five more, on the 7th eighteen, on the 

 8th eleven, and on the 12th twenty-three, this being the largest 

 number taken from the boxes at once. Beetles continued, however, 

 to emerge at frequent intervals until the 22d June, at which time 

 the last appeared, one hundred and eighteen in all, having been 

 taken alive. On the 15th September, the boxes were opened finally, 

 thoroughly searched, and hfty-three more dead Saperdas were found. 

 The boxes in which these specimens transformed, had been kept 

 under cover, but at the natural temperature of the air. 



Although the elm borer has evidently been for several years both 

 numerous and increasing in the neighborhood where this tree was de- 

 stroyed, the amount of parasitism developed by the experiments 

 was quite insignificant, only eight parasitic insects, belonging to 

 three species, appearing in the boxes as against the one hundred 

 and seventy-one examples of the adult borer; and, indeed, as the 

 same pieces of wood contained a great host of the larvae of Magdalis 

 armicollis, from which multitudes of imagos of this species emerged 

 during this spring, it is impossible to say that some or most of this 

 small number of parasites may not have escaped from the latter 

 species. 



Since the time of Harris, the elm tree borer has been well known 

 as a destructive enemy of this most magnificent and beautiful of 

 the shade trees of our towns and cities. It seems first to have at- 

 tracted attention as an enemy of the elm in Boston, in 1847, at 

 which time the trees on the Boston common were found by Harris 

 to have suffered terribly from the ravages of this insect. "Several 

 of them," he says, "had already been cut down, as past recovery; 

 others were in a dying state, and nearly all of them were more or 

 less affected with disease or premature decay. Their bark was per- 

 forated, to the height of thirty feet from the ground, with numerous 

 holes, through Avhich insects had escaped; and large pieces had 

 become so loose, by the undermining of the grubs, as to yield to 

 slight efforts, and come off in flakes. The inner bark was filled 

 with the burrows of the grubs, great numl3ers of which, in various 

 stages of growth, together with some in the pupa state, were found 

 therein ; and even the surface of the wood, in many cases, was fur- 

 rowed with their irregular tracks. Very rarely did they seem to 

 have penetrated very far into the wood itself ; but their operations 

 were mostly confined to the inner layers of the bark, which thereby 

 became loosened from the wood beneath." 



The borers, (the larvae of the beetles) are similar in form and 

 general appearance to the notorious round-headed borer of the 

 apple, belonging, indeed, to the same genus. They rarely exceed 

 three-fourths of an inch in length, are destitute of feet, and have 

 the usual enlargement of the first segment of the body immediately 

 behind the head. The body is white, subcylindrical, a little flat- 

 tened, with the lateral fold of the body rather prominent ; end of 



