41 



arranged in a double row in groups of from twenty to forty. The first 

 larva? appear about June 5th, and others continue to hatch from the 

 egg masses until after the 20th of that montli. These larva are 

 yellowish, slug-like creatures, with black dots and tubercles that are 

 set witli bunches of short bristly hair. They usually feed on the 

 under sides of the leaves and do not eat through the tissue — they take 

 only the lower layer of cells and therefore scrape rather than eat. 

 The result is that, for a time, the leaves retain their form and appear- 

 ance, and not until the larvsB are nearly full grown does injury become 

 greatly apparent. Then the foliage begins to turn brown and very 

 suddenly the tree looks as if a fire had swept through it. 



Beginning during the last days of June and continuing until the 

 middle of July, larva crawl down the trunks to the base, and there, 

 among tlae grass on the surface of the ground, they change to yellow 

 pupae. ^lany of the larvae do not come down all the way, but get 

 into the bark crevices and in such shelter change to the pupal stage. 

 Adults develop about a week after the pupa has formed, and, usually 

 about the beginning of August, the summer brood of beetles is found 

 most abundantly. In the latitude of New Brunswick, and in Xew 

 Jersey generally, there is only a partial second brood or none at all. 

 Ordinarily, the beetles that hatch in summer feed for a few days and 

 then graduallj- disappear. By the middle of August nothing more 

 is seen of them and, as a whole, they are in hibernating quarters, 

 from which they will not again emerge until spring of the year fol- 

 lowing. 



This insect has few natui-al enemies among the predatory or para- 

 sitic forms; but during the few 3-ears last past has been attacked 

 during the latter part of each summer by a disease which killed off 

 full-grown larvae and pupae in enormous numbers. For a time elm 

 trees in certain cities and throughout a large portion of the State 

 were annually defoliated to such an extent that many were killed, 

 and it became a question whether it was not really cheaper to cut them 

 out and plant other trees rather than treat with /insecticides. That 

 the insects could be kept in check was proved by work done not only 

 at Xew Brunswick but in other portions of the State; and on the 

 college campus the large elms were sprayed each year for several 

 years in succession. Then the disease already mentioned seemed to 

 establish itself more firmly each year, and for the three j-ears last 

 past it has not been necessary to make insecticide applications. 



