42 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



worm in Washington in 1886," Populus balsamifera and P. tremu- 

 loides are named among the trees that suffered most. Both these 

 poplars occur at Cedar Point, but no Avebs were observed upon them. 

 Following I give the first five trees named in Riley's list. These 

 are arranged in the order of the damage done : 



Acer negundo (box elder). 

 Populus alba (European white poplar). 

 Populus deltoicles (cotton wood). 

 Populus balsamifera (balsam poplar). 

 Populus tremuloides (American aspen). 



The same report further states that poplars, cottonwoods, and the 

 ranker growing willows were the principal subjects of attack in 1886 

 in New England. 



Of the species of trees attacked at Cedar Point, four (walnut, wild 

 black cherry, choke-cherry, and willow) appeared to be the favorite 

 food plants of the worms, and these are, respectively, 41 (Prtmus 

 xerotina is not named by Riley), 75, and 14 in Riley's list of 108 food 

 plants. In the Yearbook of the Department of Agriculture for 1895, 

 120 is given as the number of food plants listed. Again, of all the 

 species of food plants named by Riley, 42 genera and about 26 species 

 are represented at Cedar Point, but of these only 8 were observed to 

 be used as food by the worms. 



Throughout the State generally, so far as my limited observations 

 extend, and from a few other reports, the common wild black cherry 

 (Prvnvtt xerothut) is the tree most generally attacked; but walnut, 

 elm, hickory, pear, apple, sugar maple, and silver maple suffer more 

 or less. Walnut trees when attacked suffer most, as the following 

 topic will show ; and Mr. Cotton, assistant inspector of nurseries and 

 orchards, has informed me of similar conditions near Cadiz, Harrison 

 County, Ohio. 



The following observation is interesting and shows how capable 

 the female is in the selection of a favorite food plant upon which 

 to lay her eggs. One day I observed a web upon a hedge of Osage 

 orange. Closer investigation revealed the fact that the web was not 

 properly upon the Osage orange at all, but upon a small wild cherry 

 that grew there and which had escaped my notice. E. D. Sanderson ?; 

 refers to the webworm as being particularly fond of a neglected 

 Osage-orange or wild-cherry hedge. I have repeatedly observed it 

 this last summer upon wild-cherry trees that grew along an Osage- 

 orange hedge, but I do not recall seeing it upon the Osage orange 

 itself. Professor Osborn c states that he observed the webworm 



a Our Sbade Trees and Tbeir Insect Defoliators, Bui. 10, Div. Ent, U. S. Dept. 

 Agric. 



& Bui. No. 56, Del. Agric. Exp. Sta., June, 1902. 



o Insects Affecting Forest Trees. Proc. Columbus Hort. Soc, vol. 17, 1902. 



