41 



atoms. The front edge of the fore wings is grey. The antennae in both sexes are pectinatp 

 or toothed, those of the male (which are very beautiful) being much more decjily toothed 

 tlian in the female — a character by which the se.x:es maybe readily distinguished. This 

 lovely creature flies only at night, and when on the wing is of such a size that it is often 

 mistaken in the dusk for a bat. When at rest, the wings are held elevated above the 

 body, likr those of a butterfly ; but, if disturbed, they are spread out flat, both pairs being 

 shown. Early in June the moths first make their appearance, and they may be found 

 thi'oughout that month. In a few days they pair, after which the female deposits her 

 eggs, usually on the under side of the leaves of the oak, maple or hazel ; they are gene- 

 rally placed singly, but occasionally two or three may be found on the same leaf 



The egg is about one-tenth of an inch in diameter, convex above and below, with the 

 convex portions whitish and the nearly cylindrical sides brown. Mr. L. Trouvelot, of 

 Boston,, who has reared great numbers of these insects for the purpose of experimenting 

 on the silk obtained from their cocoons, gives the result of his valuable observations in 

 the first volume of the .^wcWca/j Naturalist. He says that one hundred of the eggs, on 

 the day they are laid, wUl weigh eight grains ; that one hundred and ten of the empty 

 shells weigh only one grain, and that six thousand of the newly hatched worms will weigh 

 about one ounce. They are not long, however, in increasing their weight ; in ten days 

 they weigh ten times their weight at birth ; in twenty days, sixty times ; thirty days, 

 620 times; forty days, 1,800 times; and in fifty-six days, 4,140 times their original 

 weight, having consumed in this period about one hundred and twenty oak leaves, weigh- 

 ing three-quarters of a pound. 



Fig- 26. The larva when fully 



grown appears as repre- 

 sented in fig. 26 ; it then 

 measures over three inches 

 in length, with a very 

 thick body. Mr. Trouve- 

 !' it thus describes its ap- 

 ; icarance : " The head is 

 of a light chestnut brown 

 •■ilour; the body of a 

 handsome transparent 

 ight yellowish green, with 

 seven oblique lines of a 

 pale yellowish colour on 

 each side of the body ; the 

 segments are each adorned 

 with six tubercles, giving rise to a few hairs, which are tinted sometimes with orange, 

 with a silvery spot on the middle ; there are six rows of protuberances, two on the back 

 and two on each side, and the oblique lines run between the two rows of lateral tubercles, 

 uniting the lower one to the upper one by a yellowish line. The under side of the body is 

 longitudinally striped with a faint yellowisji band ; the spiracles are of a pale orange 

 colour, and the feet are brown. The posterior part is bordered by a purplish brown 

 angular line similar to the letter V." 



Having reacluul maturity the larva begins to search about with a restless air among 

 the branches for a suitable jilace in which to construct its cocoon. The selection being 

 made, "it now," says Mr. Trouvelot, " feels with its head in all directions to discover any 

 leaves to which to attach the fil)res that are to give form to the cocoon. If it finds the place 

 suitable, it begins to wind a layer of silk around a twig, then a fibre is attached to a leaf 

 near by, and by many times doubling this fibre and making it shorter every time, the 

 leaf is made to approach the twig at the distance neces.sary to build the cocoon ; two or 

 three leaves are disposed like this one, and then fibres are spread between them in all 

 directions, and soon the ovoid form of the cocoon distinctly appears. This seems to be 

 the most diflBcult feat for the worm to accomplish, as after this the work is simply me- 

 chanical, the cocoon being made of regular layers of silk united by a gummy substance. 

 The silk is distributed in zigzag lines of about one-eighth of an inch long. When the co- 



