are on record of its occurrence in great numbers in Dutchess and 

 Sullivan counties in New York, but these occurrences were excep- 

 tional. 



LIFE HISTORY AND HABITS. 



The moths issue from over-wintering pupa3 or chiysalides in May or 

 June, according to locality, and pair, the females depositing their eggs 

 on the under side of the leaves. The number of eggs laid by a single 

 female has not been ascertained, but is known to reach at least 150. In 

 eight or ten days the eggs hatch, and the caterpillar emerges and feeds 

 and grows apace. After passing through four molts in about a month 

 it reaches full growth, when it enters the ground to transform to pupa. 

 At the end of two weeks, or a little longer, the pupa, by means of 

 the sharp and horny projections which have already been described, 

 works its way to the surface of the ground and gives forth the moth. 

 Soon afterwards the female, after copulation, lays eggs for a second 

 generation. 



In the District of Columbia it has been ascertained that there are 

 usually three generations in the course of a year, although in Missouri, 

 according to Riley, there are only two. Pupae of the second genera- 

 tion in the West and of the third generation in the East over- winter. 

 Even as far north as Massachussetts Harris showed the probability 

 of two generations annually. 



INSTANCES OF INJURY. 



Many of the earlier writers on economic entomology reported nu- 

 merous instances of injury by this species, but of late the insect has 

 not received much attention, presumably because of the far greater 

 destructiveness of the commoner tussock moth and fall webworm, and 

 of the gipsy and brown-tail moths. Possibly this maple worm is 

 decreasing in numbers. Some characteristic outbreaks may be men- 

 tioned, therefore, as showing its importance some years and to give 

 some idea of its method of work. 



In 1887 Mr. H. W. Young, Independence, Kans., wrote that for four 

 years the soft maple shade trees of that city had been defoliated twice 

 a 3'ear by this insect, the trees being greatly weakened. In 1888 Mrs. 

 M. T. McCluny, Sedalia, ]\Io., wrote that these "worms" "were like 

 the locusts of Egypt, and filled the houses" and destroyed the leaves of 

 the maple shade trees. In 1889 considerable correspondence was had 

 with j\Ir. J. W. Merchant, Kansas City, ]VIo., who reported extensive 

 defoliation in Kansas City, Kans., and sent sev^eral photographs, one 

 of which is here reproduced (fig. 2). In cases where adjoining maple 

 and elm trees branched into each other the elm trees were never 

 touched. During the period from 1888 to 18!)0, at Lincoln, Nebr., 



[Cir. 110] 



