REPORT OF THE ENTOMOLOGIST. 521 



States. The wings of the moths expand from one inch and a quarter 

 to ono inch and three-eighths. The male moth, ^yhich is usually a 

 little smaller, has its antennse doubly feathered beneath, while those 

 of the female possess instead two rows of minute teeth. 



The pupa state lasts from six to eight days for the summer brood, 

 while the hibernating brood, however, requires as many months, ac- 

 cording to the latitude. 



INJURY DONE IN 1886. 



During the past year the city of Washington, as well as its vicinity, 

 was entirely overrun by the caterpillars. With the exception of trees 

 and plants the foliage of which was not agreeable to the taste of this 

 insect, all vegetation suffered greatly. The appended list of trees, 

 shrubs, and other plants shows that comparatively few kinds escaped 

 entirely. The fine rows of shade trees which grace all the streets 

 and avenues appeared leafless and covered with throngs of the hairy 

 worms. Excepting on the very tall trees, in which the highest branches 

 showed a few leaves too high for the caterpillars to reach, not a 

 vestige of foliage could be seen. The trees were not alone bare, but 

 were still more disfigured by old and new webs made by the cater- 

 pillars, in which bits of leaves and leaf -stems, as well as the dried 

 frass, had collected, producing a very unpleasant sight. The pave- 

 ments were also constantly covered with this unsightly frass, and 

 the empty skins of the various molts the caterpillars had to undergo 

 were drifted about with every wind and collected in masses in cor- 

 ners and tree-boxes. The parks fared a little better. Because of the 

 great variety of trees planted there some escaped entirely, while 

 others showed the effect of the united efforts of so many hungry cat- 

 erpillars only in a more or less severe degree. The grassy spots sur- 

 rounding the different groups of trees had also a protective influence, 

 since the caterpillars do not like to travel over grass, except when 

 prompted by a too ravenous hunger. The rapid increase of this in- 

 sect is materially assisted by the peculiar method of selecting shade 

 trees for the city. Every street has but one kind of shade tree; rows 

 of them extend for miles, and the trees are planted so close together 

 that their branches almost interlace. Thus there is no obstacle at 

 all to the rapid increase and distribution of the cateri:)illars. If dif- 

 ferent kinds of trees had been planted so as to alternate, less trouble 

 might be experienced. Plate XI shows a view of Fourteenth street, 

 taken in late September, which illustrates the point, the Poplars on the 

 west side being completely defoliated as far as the eye can reach, 

 while the Maples on the east are almost untouched. 



As long as the caterpillars were young and still small the different 

 communities remained under cover of their webs and only offended 

 the eye; but as soon as they reached maturity and commenced to scat- 

 ter, prompted by the desire to find suitable places to spin their cocoons 

 and transform to pupae, matters became more unpleasant and com- 

 plaints were heard from all those who had to jjass such infested trees. 

 in many localities no one could walk without stepping upon cater- 

 pillars; they dropped upon every one and every thing; they entered 

 flower and vegetable gardens, porches and verandas, and tlie house 

 itself, and became, in fact, a general nuisance. 



The chief damage done to vegetation was confined to the city itself, 

 although the caterpillars extended some distance into the surrounding 

 country. There, however, they were more local and almost entirely 



