44 NEW YORK STATE MUSEUM 



most excellent results. In cities and villages where this insect is the only- 

 important enemy of shade trees, this system or the payment of a bounty 

 on eggs collected would undoubtedly result in the pest being kept in 

 subjection at a comparatively small outlay. It may also be controlled 

 by spraying, which will be discussed under a separate heading. 



ELM LEAF BEETLE 



Galerucella luteola Mull. 



Along the Hudson river valley as far north as Troy, this insect is the 

 worst enemy of the elms, specially the European forms, though under 

 certain conditions it may inflict much injury on the American elms. So 

 far as known, this pest has not made its way to any great distance from 

 the Hudson river in this state, excepting on Long Island. 



Characteristics. The elm leaf beetle is about \ inch long with 

 the head, thorax and margins of the wing covers a reddish yellow. The 

 coal black eyes and median spot of the same color on the head are 

 prominent. Its other black and yellowish or yellowish green markings 

 may be made out by aid of figure 2, plate 1. They are usually constant 

 in the adult, but the colors are quite variable during life and change 

 more or less after death. In some beetles emerging from winter 

 quarters, the conspicuous greenish yellow stripes of the wing covers are 

 nearly black. In the early spring the beetles are found in houses, 

 sheds and other shelters where they pass the winter. On the appear- 

 ance of the foliage, from about the first to the middle of May, the 

 beetles fly to the trees and, after eating roundish holes (pi. 2, fig.- 1) for 

 some time, deposit their yellowish eggs in irregular rows side by side, 

 forming clusters of from 5 to 26 or more (pi. 1, fig. 3), over half the 

 total number of eggs laid being deposited between about the 10th and 

 20th day after oviposition begins, comparatively few being laid from 

 the 20th to the 30th days. 



The young grubs (pi. 1, fig. 4), about ^- inch long and well pro- 

 vided with black tubercles and rather long hairs of the same color, 

 appear early in June and feed only on the under surface of the leaves 

 (pi. 2, fig. 2). They complete their growth in from 15 to 20 days 

 and the mature ones (pi. 1, fig. 5) may be recognized by the broad 

 yellow stripe dorsally and a narrower stripe of the same color on 

 each side, the yellow stripes being separated by broad dark bands 

 thickly set with tubercles bearing short, dark colored hairs. The full 

 grown larvae or grubs descend the trees and transform to orange 

 yellow pupae (pi. 1, fig. 7) in the crevices of the larger limbs and trunks, 

 and on the ground around the base of the trees, where they sometimes 



