336 KEPORT OF THE COMMISSIONER OF AGRICULTURE. 



The recently-excluded larvse are uniformly curled up on the under 

 side of the leaf. 



Three varieties of cultivated willows were found to be injured by the 

 perfect saw-fly, while egg-blisters could only be found on two varieties. 



REMEDIES. 



It would be quite practicable, considering the small area to be pro- 

 tected and the conspicuous size of the insect and its clumsy movements, 

 to catch the perfect flies by means of a net ; but the application of ar- 

 senical poisons would be surer, and would also rid the willows of many 

 other enemies. 



The most numerous and most dangerous of these enemies is, beyond 

 question, the Willow Galeruca {Galeruca decora Say), of which young 

 larvae and imagos were met with everywhere on the leaves. The char- 

 acter of its injury and its natural history do not appear to differ from 

 those of the Imported Elm leaf-beetle (G. xanthomel(tnn). Its eggs are a 

 little larger, brighter colored, and less acuminate, and the young larvae 

 of darker color, but not otherwise different. Full-grown larvae were not 

 found early in June and only a few egg clusters. Next in number comes 

 Colaspis tristis, which in the imago state preferably feeds upon the very 

 young, not yet fully developed, leaves. Its larva, whmh no doubt has 

 subterranean habits, was not met with, and it probably feeds on the 

 roots of some other plant. 



THE STREAKED COTTONWOOD LEAF-BEETLE. 



(Plagiodera scripta, Fabr.) 



Order Coleoptera; Family Chryso^ielid^:. 



[Plate VHI3 Figs. 1, 2.] 



On account of its rapid growth and great hardiness, as well as its 

 beauty as a tree, the Cottonwood [Populus monilifera) has been exten- 

 sively planted throughout the treeless portions of the West. Its insect 

 enemies are not numerous, but two of them are extremely destructive, 

 and, unless measures are taken to avert their injury, will soon make 

 the growing of this tree a matter of difficulty. The first of these, the 

 Cottonwood Borer [Saperda calcarata Say), we shall not treat at this 

 time, as its injuries have not, of late, been comparable with those of the 

 insect which forms the subject of this article. 



DA3IAGE DONE IN 18S4. 



During the past season the Streaked Cottonwood Leaf-beetle tins 

 done great damage in portions of Nebraska and Dakota. Appearing 

 in enormous numbers, it has entirely defoliated many thousands of trees, 

 and has destroyed many plantations of young saplings. The strip of 

 country over which it has been particularly injurious has been along 

 the banks of the Missouri River in Dakota, as far west as its junction 

 with the Niobrara, and thence down through Nebraska to the Platte, as 

 Tar west as Dawson County. As a sample of the many communications 

 which 4ave been received during the summer from the infested region, 



