POPLAR BORERS. 443 



This I believe is a true Cossus, although the male is not known to me. The shape 

 of the w ing is as in centerensis. The structure is that of Cossus, and not of Prionoxystus. 

 The thorax is subquadrate, the vestiture short and thick. The interspacial black 

 dashes along the primaries snbterminally distinguish it specifically. The pre-apical 

 transverse black streak or line resembles that of C. centerensis. The hind wings are 

 faintly reticulated. The ground color is a yellowish white. The black blotches on 

 fore-wings of rohiniw are here wanting, while there is a diffuse discal shade blotch, 

 another above and beyond it on costa, and the wing shows a wide, soft, blackish 

 shading, obliquely edged inwardly and covering the outer portions of the wing. 

 Except the antenuie my type is perfect. Beneath it is strongly marked, and reminds 

 one of C. robiniw Peck, but the shape of the wing is not like that species. The 

 thorax is black above, not gray with black stripe or teguhe, and the collar is dis- 

 colorous, pale yellowish gray. This species ought to be recognizable. The shape of 

 the thorax is like Cossus, as is the vestiture, so that I am not prepared to find that 

 the male has the peculiarities of C. robinice and querciperda Fitch. I hope Western 

 collectors will sol^e the question. But I can not regard angrezi as having anything 

 to do with the question of a Western representative of robinke. From Herrich 

 Schaeifer's figure, and what has been published, I believe that robinice is found across 

 the continent. (Dr. Bailey, I, c.) 



9. The lombardy poplar borer. 



Agrilus granulatus Say. 



Order Coleoptera ; family Buprestid^. 



The following account of this borer is by Prof. T. J. Burrill, and is 

 taken from Forbes' First Annual Report on the Injurious Insects of 

 Illinois. 



It is known by every one that the Lombardy poplar lives but a short time in the 

 rich soils of the Mississippi Valley, where its growth is exceedingly rapid. Many 

 suppose that this is due to some degeneration, through the processes of propagation 

 or otherwise, of the constitutional vitality of the tree — that it is inherently short- 

 lived. 



After some studies upon this subject, I am quite sure that the early death of the 

 tree comes from other causes, and is due to agencies outside the tree itself and not 

 specially connected with the soil or climate. For the present note, one of these, 

 and only one, may be mentioned. 



About the middle of June a small beetle {Agrilus granulatus Say) lays its eggs in 

 the crevices of the rongh bark, depositing them singly here and there, but some- 

 times only an inch or two apart, on the trunk and limbs old enough to become rough- 

 ened by the fissures and cracks of the outer bark. The larvie penetrate the living 

 bark and gnaw tortuous galleries in it and the young layer of wood just beneath. 

 These galleries are at first as fine as the puncture of a cambric needle, and never 

 become larger than one-tenth of an inch in diameter. For the most part th.jy run 

 in irregularly horizontal directions, or crosswise of the grain of the wood. When 

 numerous, as they often are, they sometimes cross each other, but this is uncommon. 

 They are closely packed with the excrement of the larvae. 



The latter are exceedingly slender, slightly flattened, much elongated, footless and 

 white ; the first segment of the thorax is somewhat enlarged, and the minute but 

 sharp jaws apparently project from its front. In October they bore obliquely into 

 the deeper layers of the wood, often one to two inches from the surface, and then 

 usually follow the grain up or down some inches, and turn obliquely outward until 

 within about an eighth of an inch of the surface wood, though this distance varies 

 much. The last inch or thereabouts of the burrow is greatly widened and ends with 

 an obliquely rounded termination. The long, slender larva, towards tlie last of this 



