THE FALL WEB-WORM. 4l 
the caterpillars. If different kinds of trees had been planted, soas to 
alternate, less trouble might be experienced. Plate I shows a view 
of Fourteenth street, taken late in September, which illustrates this 
point; the poplars on the west side being completely defoliated as 
faras the eye can reach, while the maples on the east are almost un- 
touched. 
“As long as the caterpillars were young, and still small, the dif- 
ferent communities remained under cover of their webs, and only 
offended the eye. But as soon as they reached maturity, and com- 
menced to scatter—prompted by the desire to find suitable places 
to spin their cocoons and transform to pupze—matters became more 
unpleasant, and complaints were heard from all those who had 
to pass such infested trees. In many localities no one could walk 
without stepping upon caterpillars; they dropped upon every one 
and everything; they entered flower and vegetable gardens, porches 
and verandas, and the 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 
confined to certain trees, and mainly so to the White Poplar and the 
Cottonwood. Along the Baltimore and Potomac Railroad tracks these 
trees were defoliated as far as five miles from the Capitol. In George- 
town the caterpillars were equally noxious, but in the adjoining forests 
but very few webs could be seen. 
“The proportionate injury to any given species of tree is to some 
extent a matter of chance, and in some respects a year of great injury, 
as 1886, is not a good year to study the preferences of a species, be- 
cause when hard pressed for food the caterpillars will feed upon al- 
most any plant, though it is questionable whether they can mature 
and transform on those which they take to only under the influence 
of such absolute necessity. Again, the preference shown for partic- 
ular trees is more the result of the preference of the parent moth 
than of its progeny in a case of so general a feeder as the Fall 
Web-worm. We hada very good illustration of this in Atlantic City 
last autumn. The caterpillars were exceedingly abundant during 
autumn along this portion of the Atlantic coast, especially on the 
trees above named. We studied particularly their ways upon one 
tree that was totally defoliated by September 11. The bulk of the 
caterpillars were then just through their last molt, though others were 
of all ages illustrating different hatchings. There was an instinctive 
migration of these larve of all sizes, and the strength of their food 
habits once acquired from birth upon a particular tree was well 
illustrated. At first the worms passed over various adjacent plants, 
like honeysuckles, roses, etc., the leaves of which they freely devour if 
