12 . NEW YORK STATE MUSEUM 



Life history. The transformations of this insect are so rapid and 

 so greatly influenced by local conditions that a man must know what 

 to expect or he will accomplish very little in fighting the pest, because 

 a substance effective against the beetles or grubs may not kill the 

 pupae and, after the larvae have begun to descend, may be of no 

 value. The beetles winter in attics, sheds, outhouses and other 

 shelters. They emerge with the advent of warm weather and may 

 then be found on the walks during the sunny portion of the day or 

 at the windows of houses, trying to escape. The last of April or 

 early in May, with the appearance of the foliage, the beetles fly to 

 the elms and eat irregular holes in the leaves. Some time is occu- 

 pied in feeding before the deposition of eggs, a process which may 

 continue four and possibly five or six weeks. The prolific beetles 

 consume a large amount of foliage during this time, depositing 

 clusters of from 3 to 26 or more eggs every day or two. Over half 

 the total number of eggs may be laid at the hight of the season 

 within about 12 days; in 1898, from June t2 to 23. A female may 

 produce over 600 eggs. 



The young grubs appear early in June or about five or six days 

 after the eggs have been deposited later in the season. They feed 

 on the under surface of the leaf, producing the familiar skeletoniza- 

 tion [pi. 2, fig. 7] which is caused by their eating the softer under- 

 part, leaving the veins and the upper epidermis practically 

 untouched. The results of their feeding are so marked that it is 

 easy to detect the presence of the grubs by the semitransparent 

 patches in the foliage. These latter soon dry and turn brown. 



There are two and occasionally three generations of this destruc- 

 tive insect in the latitude of Albany, the number depending to a 

 considerable extent upon the availability of suitable food. The 

 grubs complete their growth in from 15 to 20 days, descending limbs 

 and trunk to a great extent in search of some shelter under which 

 to pupate. Seven days are spent in this latter state in warm July 

 weather, while in September it is extended to 12 and in October to 

 24 days. The grubs of the first brood usually forsake the trees in 

 Albany by the last of June or early in July, and beetles belonging to 

 the second generation may begin depositing eggs about the middle 

 of July, and from then to late in autumn it is generally possible to 

 find this insect in all stages in some part of Albany. The beetles of 

 the second brood are naturally attracted to fresh foliage and conse- 



