240 FIFTH KEPORT OF THE ENTOMOLOGICAL COMMISSION. 



upon. For aboMt two days they reoiaiii close to their birthplace, eating only the 

 parenchyma of the leaf, and showing so little inclination to travel that, shoukl the 

 leaf by accident be detached, they perish rather than search for another. They have 

 at this stage of growth the curious habit, when disturbed, of raising the abdomen to 

 a nearly perpendicular position, holding on to the leaf very firmly with their jaws. 

 They are at this time of a glossy yellow color, and generally shed the first skin two 

 days after birth, the empty skin adhering tightly to the leaf. 



In the second stage, the color of the worms becomes more brownish, and they are 

 more active, but still remain clustered together upon a single leaf or branch, scatter- 

 iug but slightly in proportion as they skeletonize one leaf after another. They yet, 

 for the most part, feed upon the under side of the leaf, not touching the upper skin, 

 and giving to the leaves a brownish, speckled, and seared app earance, as if covered 

 by patches of some brown fungus. The excrement is voided in long, bead-like 

 strings, which cover the ground or hang down from the branches and leaves of the 

 infested trees. In another week, or when the larvae are about half grown, a second 

 molt takes place, they preparing for it in the usual manner by firmly attaching the 

 anal joints to the leaf. (Fig. 83, e.) In the beginning of the third stage they 

 feed indiscriminately on either side of the leaf, but still refuse to touch the epidermis 

 of the opposite side. The gnawings on the upper side at this stage of growth are 

 peculiar, being in the form of crescent lines with narrow strips of epidermis between 

 them; whereas on the under side there is no such regularity, and all is eaten but the 

 stronger cross veins. I have been unable to trace any further molts. This third 

 stage lasts from two to three weeks, the larvae scattering more thoroughly and the 

 general color becoming qftite brown or yellowish-brown. As the worms reach full 

 growth (Fig. 83, ddd) the fleshy part of the leaves is entirely eaten so that little 

 remains but the principal ribs, and the leaves thus present a very ragged appearance. 



Toward the end of July and early in August the worms cease feeding and descend 

 into the ground, burrowing therein and forming a simple oval cavity a few inches 

 below the surface. They lie dormant therein through the fall, winter, and early 

 spring mouths, assuming the pupa state (Fig. 83, i) but about a week before the 

 beetles issue. 



Remedies. — Experiments made upon the larva of the imported elm-leaf beetle shows 

 that Paris-green water is very effective in destroying it, in both the larva and beetle 

 states ; and, while I have had no opportunity of making such experiments with the 

 species in question, I have no doubt that it would here prove equally destructive. 

 The larvtB are, throughout their existence, quite sluggish and drop to the ground on 

 slight disturbance. A good shaking of an infested tree, therefore, will bring most of 

 them to the ground, and experience shows that they have little or no capacity for 

 mounting the tree agaiu. This remedy will be applicable to cultivated trees, espe- 

 cially before they get too large. 



24. The interrogation — mark butterfly. 



Grapla interrogationia (Fabricius). 



Injuring the foliage of the elm as well as linden tree and hop-vine, a caterpillar, with 

 reddish black, bilobed head, and black body covered thickly with streaks and dots 

 of yellowish white, transforming into our largest species of Grapta, and marked on 

 the under side of the dull hind wings with a golden semicolon. 



I am informed by H. L. Clark, esq., that in 1887 the elms in Provi- 

 dence were much eaten and disfigured by these caterpillars, and that 

 the chrysalids were everywhere to be seen attached to fences, walls, etc. 



Larva. — An inch and a quarter long. The head is reddish black, flat in front and 

 somewhat bilobed, each lobe tipped with a tubercle emitting five single black pointed 

 spines. It is covered with many small white and several blackish tubercles. The 



