40 OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 



tawny-yellow front thighs, and blackish feet; in some specimens the 

 tawny thighs have a large black spot, while the shanks on the upper 

 surface are rufous. In many all the thighs are tawny yellow, while in 

 others they have scarcely any color. Some specimens (often reared 

 from the same lot of larva 3 ) have two tolerably distinct spots on each 

 front wing — one at base of fork on the costal nerve and one just within 

 the second furcation of the median nerve. Other specimens, again, 

 have their wings spotted all over, and approach the form punctatissimcij 

 described as the " Many-spotted Ermine-moth" of the Southern States. 

 The wings of the moths expand from 1^ inches to If inches. The male 

 moth, which is usually a little smaller, has its antennae doubly feath- 

 ered beneath, and 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 in which they occur. 



INJURY DONE IN 18S6. 



" 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 line 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 dis- 

 figured by old and new webs made by the caterpillars, in which bits of 

 leaves and leaf-stems, as well as the dried frass, had collected, produc- 

 ing a very unpleasant sight. The pavements were also constantly cov- 

 ered 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 corners 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 caterpillars only in a more or less severe 

 degree. The grassy spots surrounding 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 insect is materially assisted by the peculiar method of 

 selecting shade trees for the city. Each street has, in many cases, 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 



