THE ELM-LEAF BEETLE IN NEW TOEK STATE 13 



Number of generations. The detailed observations of the 

 past two years have established beyond question the presence of 

 two well marked generations and the occurrence of an incom- 

 plete third brood under favorable conditions at both Albany and 

 Troy. In these two cities the insect has continued breeding so 

 long as the elms afforded sustenance. This is the more remark- 

 able since Dr rSmith records but one brood a year, or one and a 

 partial second at New Brunswick, N. J., a point about 150 miles 

 to the south. As is well known, most insects are more destruc- 

 tive soon after their introduction than in later years. This may 

 be accounted for by the fact that in time native parasites, dis- 

 eases and other natural checks gradually assert their power upon 

 new comers. An insect's freedom from natural enemies might 

 have some effect upon its prolificacy, and possibly upon the num- 

 ber of generations. It will not only be of interest, but of great 

 practical importance to ascertain by observations whether this 

 beetle continues to produce two or three generations yearly in 

 this latitude. 



Habits of beetle and larvae. Certain habits of this in- 

 sect are of great value when the problem of controlling it comes 

 up for solution. Its hibernation affords no vulnerable point as 

 the beetles are then too scattered to admit of effective work 

 against them. In the spring they feed on the young leaves for 

 two or three weeks and when abundant may cause considerable 

 injury. The irregular round! holes seen in the young leaves (fig. 

 2) are an indication of the presence of this pest. Under excep- 

 tional circumstances the beetles may eat the under surface of the 

 leaves, refusing the veins and tough upper epidermis. This only 

 occurs when the foliage is unusually hard and dry. 



One habit the adult insect possesses, which is of much im- 

 portance, is its disinclination to fly a great distance. The 

 instinct within this beetle to remain near one spot is so marked 

 that it spreads very slowly indeed. This is clearly shown in its 

 taking seven years 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 one and one half miles. I have repeatedly 



