So6 BULLETIN 333 



the larvae pupated in abundance. Several adult beetles were observed 

 emerging from scores of pupae at the bases of trees on July 8. 



On July 17 many beetles were noted on the leaves of the elms, but no 

 eggs were found. On July 20, however, H. H. Knight discovered a bunch of 

 twelve eggs that had been deposited by a beetle found in the field on July 8. 

 This beetle had been confined in a cage in the insectary. On July 27 

 and July 30 Mr. Knight found an abundance of eggs of the second brood 

 on some English elms in the city of Ithaca. Some of these eggs were 

 already hatching, which showed that they had been deposited several 

 days earlier. By the first week in August the eggs of the second brood 

 were hatching in abundance. The English elms, on which the eggs were 

 found, had been practically defoliated by the first brood, not having 

 been sprayed; these trees had put forth a growth of new leaves. By 

 September i many larvae had left the trees and a few pupae were found 

 at the bases of the English elms. Most of the pupae of this second brood 

 were destroyed by the fungus Sporotrickum globuliferum. It is possible 

 that there is a partial third brood in Ithaca in favorable seasons, such 

 as that of 1911, for example. The history of the beetle was not followed 

 in detail further than the first week in September during that season, 

 but in the latter part of September the writer noted what were apparently 

 nearly full-grown larvae on elm leaves. These were possibly the larvae 

 of the third brood. 



Doctor Felt 1 has noted a partial third generation under favorable con- 

 ditions in the vicinity of Troy and Albany. 



In 1912 the conditions were very different from those in 1911, for the 

 beetles appeared much later in the season. In fact, they appeared so 

 late that it was thought they were not coming in any abundance and 

 would do no great harm. They came late in the season, however, and 

 did considerable damage where no spraying was done. 



In 1910 the writer stated, " Our observations show that in Ithaca 

 we have one generation, with a possible second, the latter, however, 

 being so small as to cause no serious damage." 2 The observations on 

 which this statement was founded were made in 1910. The season of 

 1910 was similar to that of 1912, in which the beetles appeared late. 

 In 1910 and 1912 the second generation was apparently small and did 

 little damage, especially on the American elms where these observations 

 were made. This is a fair illustration of the absurdity of drawing general 

 conclusions and deducing general principles regarding the activities of 

 an insect, from observations carried on during only one season. More- 

 over, it would seem that these insects, at least in Ithaca, are much more 



1 Bulletin 20, New York State Museum, 1898, p. 13. 



8 Circular No. 8, Cornell University Agricultural Experiment Station. 1910, p. 4. 



