156 



had an insect foe peculiar to itself. In the late summer of 1890 the 

 hedges in and around Kirkwood and throughout St. Louis County- 

 gave evidence of some unusual insect work. The leaves were some- 

 what webbed and eaten into holes so numerous and close together that 

 they had the appearance of very open-meshed lace. Of many only the 

 midrib and larger veins remained. Repeated examinations failed to 

 reveal any insect in numbers at all corresponding to tlie amount of 

 damage, and for that year the depredator escaped recognition. 



Last September, however, the mystery was solved by the discovery, 

 on the under side of 'a leaf, of several slender, watery-green larvie of Pyr- 

 alid afiflnities, extended close to and along the veins. Having once ob- 

 tained a clue to their appearance and habits they were found to be very- 

 numerous and of all sizes, from those only one-eighth inch in length and 

 no thicker than a thread, to those three-fourths of an inch long by one- 

 tenth in diameter. The colors are remarkably imitative. Up to the 

 third molt they are of a whitish translucent green and it is almost im- 

 possible to distinguish them stretched out along the veins of the under 

 surface. After the last larval molt they assume the pale grayish indis- 

 tinctly mottled color of the bark of the mature wood of the plant. These 

 colors, in connection with their habit of feedfng only at night and of 

 retiring during the day to the interior of the hedge, where the young , 

 rest in security on the under sides of the leaves, while those more nearly- 

 mature stretch themselves along the stems, render them among the 

 most illusive of larvfc, and after I had reared them in the breeding cage 

 as well as carefully noted their traits in the open air, I was not sur- 

 prised that they had for so long successfully evaded detection in spite 

 of the evidences of their presence in the ragged and sickly appearing 

 foliage. 



Til ere are two distinct broods annually, but the moths issue irregularly, 

 live for a considerable time, and the larv.ne grow rather slowly, so that 

 the latter may be found in greater or less numbers from the middle of 

 May until the latter part of October. 



The moths begin to emerge in the spring about the first of May, and 

 shortly after begin ovipositing. 



The eggs are laid in little masses of from 25 to 30 on the under sur- 

 faces of the leaves. They are oval, flattened, .5™™ in lengtn, pale green, 

 shading to a whitish margin, and overlap like the scales of a fish, but 

 not so regularl3\ They are attached and protected by a varnish-like 

 fluid extruded with them, which hardens upon exposure to the air. 

 The larvoB hatch, simultaneously, in seven or eight days, and remain in 

 company for a short time, gnawing the parenchyma in small si^ots from 

 the under surface of the leaf on which they are hatched. They are at 

 first about 2°^"" in length, very slender, and of a pale translucent green 

 color. They spin a slight web, and if the plant is shaken let them- 

 selves down by an invisible thread. After the first molt they separate, 

 seldom more than two or three of a size being afterwards found upon 

 the same leaf. 



