TBTB 



Entered, accordii 



NEW YORK, JULY. 1880, 



No. 7. 



PUBLISHED MONTHLY BY 



THE HUB PUBLISHING CO. of n. 



828 Pearl St., New Vork. 



TERMS Two dollars per annum, in advance. 



EDITORS : 



CHAS. V. RILEY, Editor Washington, D. C. 



A. S. FULLER, Assistant Editor, Ridgewood, N. J. 



A FOE TO COTTONWOOD. 

 The Streaked Cottonwood Beetle. 



" A subscriber at Lone Star, Butler County, 

 Neb., writes that an insect is doing great 

 damage to the cottonwood trees in that locality. 

 The letter was received some time ago, but it 

 will be impossible to give a positive answer 

 from the few notes given. The short descrip- 



[Fig. 61 



Plagiodera scripta . a, eggs ^, one enlarged ; <r, newly hatched larvae ; ^/, d, d, 

 larvae of different sizes ; «, pupa — natural size; _/", one of the middle joints of body of larva 

 from above, showing tubercles — enlarged (after Riley). 



tion given would indicate that the insect of 

 which the writer speaks is a beetle, and belongs 

 to the ChrysonielidcE, but I know of no species 

 of this leaf-eating group which injures the Cot- 

 tonwood. I will be glad to determine it if the 

 party will send me specimens of the beetle, 

 or if specimens cannot be found, an exact de- 

 scription of how it works, the part of the tree it 

 injures, and the time of year it is found." — Cyrus 

 Thomas, in Prairie Far7ner. 



The insect referred to is beyond doubt 



the Plagiodera scripta Fabr., a most abund- 

 ant species infesting Cottonwood and other 

 species of Populus throughout the West 

 and south to Louisiana. We have received 

 it from many of our correspondents in Ne- 

 braska and other western States, and all 

 report it as destructive to the leaves of the 

 Cottonwood. 



In the New York Weekly Tribune for 

 Oct. 9, 1878, we first drew attention to this 

 insect in the following words : 



This insect has long been known to affect our 

 willows, but not usually to an injurious extent. 

 The larva is peculiar for emitting from the tips of 

 its tuberculous spines a milky fluid which has a 

 peculiarly pungent but not 

 altogether disagreeable odor. 

 It transforms on the leaf by 

 fastening its hind legs to it, 

 and the pupa remains with- 

 in the partially thrown off 

 larva skin. The beetle is 

 one of the most variable 

 species we have. The typical 

 form has the thorax black 

 with the sides yellow, except 

 a small spot each side, and 

 the wing-covers yellowish, 

 with three interrupted lines 

 of black or bluish spots. In 

 the varieties these spots 

 either diminish in size or 

 they increase, and specimens 

 are not rare where the wing- 

 covers are of a uniform black- 

 ish blue. In rare cases the 

 whole beetle, including the 

 thorax, is uniformly blue. 

 The interesting feature about 

 this insect to the forester, 

 however, is that it has of late 

 years acquired an especial 

 liking for the Cottonwood. 



It has, indeed, become a most grievous pest in 

 the prairie States, where the Cottonwood is largely 

 grown as a shade and ornamental tree, as well as 

 for fuel. We have been surprised, in passing 

 through Kansas and Nebraska more particularly, 

 at the utter devastation which this beetle has pro- 

 duced. Vast groves have been destroyed through 

 its incessant defoliation. Now the Cottonwood is 

 placed by botanists in a genus different from that 

 of the Willows, and the strangest thing about it is 

 that the Willows are not injured to the same de- 



