SECRETARY'S REPORT. 153 



the tree, and forestalls the intentions of the embryo invaders 

 by collccthig and depositing them safely in tlie kitchen fire. 

 Then, when his less informed or more indolent neighbors are 

 lamenting their vanished prospects, or hurriedly snatching an 

 ill-spared moment to endeavor to arrest the wholesale destruc- 

 tion, he can enter calmly into the various employments of the 

 spring, while his fresh and blooming trees all the greener and 

 fresher by the contrast, proceed to fulfil the promises of autumn 

 wealth. 



These ravenous insects pertain to a group called Bombycidce, 

 or silkworm moths, which are generally distributed through the 

 globe. The adult insects are frequently of the largest size, and 

 of variegated and brilliant colors, the wings of some containing 

 large membraneous transparent spots, devoid of scales, and 

 presenting a singular appearance ; the species from whose cog- 

 coons the silk of commerce has been hitherto obtained are of 

 plainer colors, generally approaching a dirty yellowish white, 

 and of smaller size. Experiments which have recently been 

 made in this country, seem to prove that one or more of o^lr 

 common native attaci are capable of producing silk of the finest 

 texture and great strength. Dr. J. G, Morris, of Baltimore, 

 has been very much interested in developing the capabilities of 

 the Attacus cynthia, which feeds upon the ailantlms tree, and 

 M. Trouvelot, of Medford, in this State, has demonstrated that 

 the Attacus polyphemus, which feeds upon our commonest forest 

 trees and shrubs, produces a beautiful silk in greater quantity 

 than the original silkworm, and at far less expense to the 

 cultivator. 



Our apple-tree is frequently attacked by the largest American 

 Bombyx, the Attacus cecropia, which appears in the form of a 

 peagreen worm, or larva, about three inches in length, orna- 

 mented with little knobs, or warts, on the back, of blue and 

 red. It seldom occurs in sufficient numbers to prove very 

 injurious, but one larva devours several pounds of foliage 

 before coming to maturity, and when discovered should receive 

 the usual treatment of an enemy. It is rare, however, that 

 more than one or two are found upon upon a single tree. The 

 moth frequently measures six and a half inches from tip to tip 

 of its expanded wings, and is-of a dusky grayish brown color, 

 spotted and banded, with a variety of colors, the most con- 



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