504 BULLETIN 333 



the score. Housekeepers are sometimes alarmed when they see so many 

 of these beetles crawling on their windowpanes, walls, and ceilings, 

 thinking that probably here is another household pest. Fortunately, 

 so far as the writer is aware, these insects do not injure household articles 

 of any description. Other individuals hide under loose pieces of bark 

 on trees, in cracks in fences and telegraph poles, in outhouses, sheds, and 

 any other sheltered places that they are able to find. Here they remain 

 in a quiet, inactive condition through the long winter months. With 

 the warm days of spring the beetles awake and begin crawling about 

 on the walks and on the windowpanes. 



As soon as the leaves of the elm begin to appear the insects fly to the 

 trees for their first spring meal. After feeding for some time they deposit 

 their conspicuous orange-colored eggs (Fig. 173) in clusters of five to 

 twenty-five on the undersides of the leaves. The egg is flask-shaped, and 

 stands upright with its larger end attached to the leaf. The eggs hatch 

 in five or six days during hot weather, but in cool weather this period may 

 be prolonged several days. The grubs eat ravenously, increase rapidly 

 in size, and complete their growth in fifteen to twenty days. When full- 

 grown they either crawl down the trunk of the tree or drop from the 

 ends of the branches. At the bases of the trunks many of the larvag 

 transform into the yellow pupae (Fig. 176). Sometimes they are so 

 numerous that the pupae lie an inch deep about the foot of the tree. 

 Other larvae undergo transformation in crevices of the bark, espe- 

 cially if the trunk of the tree is rough; others go to gutters; while still 

 others seek shelter in crevices of the sidewalk and wherever they can 

 find hiding-places. The quiet, inactive pupae lie motionless for six to 

 ten days and then transform into adult beetles, thus completing the life 

 round of one generation. 



Observations on the life cycle and number of generations at Ithaca 



During the last week in April in 1911 the beetles became active and 

 were especially evident on the windowpanes of dwelling-houses. By 

 May 2 the elm trees were blooming and the leaf buds were beginning 

 to show green. By May n the trees were beginning to come into leaf 

 rapidly and some were fairly well in leaf. The beetles were present at 

 this time on the leaves and were eating ravenously. On May 16 eggs 

 were found on the leaves ; they were probably deposited a few days earlier. 

 On May 18 eggs were found in some abundance on the English elms. 

 On May 22 the first eggs were hatching; during the succeeding two 

 weeks the eggs were hatching in abundance. By June 18 a few larvae 

 were found pupating, and from that time into the first week in July 



