8S THE FOREST TENT CATERPII.LAK 



almost as effectually as does the honey-bee in the formation of 

 its hexagonal cells." 



ABUNDANCE AND INJURIES 



The injuries caused by these caterpillars have been serious 

 and widespread. In many regions they have defoliated the 

 maples of sugar groves. In ^ome cases the trees have been 

 killed, while in others their vitality has been so weakened that 

 they became, at least temporarily, of little value for sugar pro- 

 duction. When syrup is made from such trees, it is of such 

 inferior quality that it is often locally called " bugg}' syrup." 

 All through the infested regions hillsides may be seen in which 

 the woods are brown and bare from the attacks of the cater- 

 pillars. 



It is difficult for one who has not seen an outbreak of such 

 a pest as the Forest Caterpillar to get an adequate conception 

 of the enormous numbers which may be present. They have 

 been collected, quarts at a time, in many localities, and are 

 often so abundant on the trunks of trees as to conceal the bark 

 from view. An idea of the mass which may migrate from 

 one place to another may be obtained from the account alreadv 

 given of their stopping railroad trains (p. 85). 



The effect of a sudden onslaught of an army of these cater- 

 pillars migrating from a neighboring woodland to an apple 

 orchard may be disastrous. Defoliation may take place in so 

 short a time that the leaves are gone before the presence of the 

 caterpillars is known. In many cases a new crop of leaves 

 will be put out, but the vitality of the trees is necessarily 

 impaired. 



DATES OF TRANSFORMATIONS 



The statement has alreadv been made that there is consider- 

 able variation in the time of hatching of the caterpillars. By 

 the middle of June, when some of the larv^ had become full- 

 grown and spun cocoons, others had only moulted once, and 

 many others only twice. The majorit3' of the caterpillars spun 

 up by June 25, and practically all by the 30th of the same 

 month. Many of these caterpillars which spun latest were 

 much smaller than the normal size. The earliest moths 

 emerged about June 24. 



