ELM LEAF BEETLE IX NEW YORK STATE 15 



affords no vulnerable point as the beetles are then too scattered 

 to admit of effective work against tlicni. They feed on the young 

 leaves in the spring for two or three weeks and when abundant 

 may cause considerable injury. The irregular round holes in 

 the foliage (pi. 1, fig. 9 and pi. 7, fig. 2) are an indication of the 

 presence of the beetles, and the amount of injury gives some idea 

 of their abundance. Under exceptional circumstances they may 

 eat the under surface of the leaves, refusing the veins and tough 

 upper epidermis. This is only when the foliage is unusually 

 hard and dry. 



One habit of much importance which the adult insect pos- 

 sesses is its disinclination to fly a great distance. Its instinct 

 to remain near one spot is so strong that it spreads very slowly 

 indeed. This is clearly shown in its taking seven j-ears to make 

 its way in numbers from the point where it established itself 

 first in this city to Washington park, a distance of less than 

 1^ miles. We have repeatedly seen European elms badly defoli- 

 ated and within 50 feet others of the same species would be 

 hardly affected. In three years (1895-98) it made its way along 

 certain rows of European elms in Albany at the rate of about a 

 block a year. 



The larvae are very rarely found on the upper part of the 



leaf; they appear on the under surface and feed there almost 



exclusively. It is also evident that in most cases trees are 



attacked near the top, probably because the foliage of the upper 



portion is more tender and clean. This is well shown on pi. 3, 



where the dead tips are high, showing conclusively the prefer- 



* 

 once the beetles have for the younger leaves. 



The larvae forsake the leaves after attaining their growth 



and may be found crawling along the limbs and trunk. If the 



tree has comparatively smooth bark, a far greater portion make 



their way to the ground in search of proper shelter while 



passing through the pupa stage, than if it has a rough bark, 



which affords numerous secure crevices in which the final 



changes may be effected. At this time the trunks of infested 



trees present an interesting sight as thousands of the grubs 



