THE FALL WEB- WORM. 41 



the caterpillars. If different kinds of trees bad been planted, 

 alternate, less trouble might be experienced. Plate I shows a view 

 of Fourteenth street, taken late in September, which illi this 



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 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 pupae — 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 1880, 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 had a 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 larvae 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 



