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 Prionoxj/stus. 
The thorax is subquadrate, the vestiture short and thick. The interspacial black 
dashes along the primaries subtermiually distinguish it specifically. The pre-apical 
transverse black streak or line resembles that of C. centerensis. The hind wiDgs are 
faintly reticulated. The ground color is a yellowish white. The black blotches on 
fore-wings of robinice 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 antennae my type is perfect. Beneath it is strongly marked, and reminds 
one of C. robinice Peck, but the shape of the wing is not like that species. The 
thorax is black above, not gray with black stripe or tegulse, 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 solve the question. But I can not regard angrezi as having anything 
to do with the question of a Western representative of robinice. From Herrich 
Schaeffer'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 Bupresthxe. 
The following account of this borer is by Prof. T. J. Burrill, and is 
taken from Forbes' First Annual Eeport 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 aud 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 rough 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 larvae 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^y 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, aud 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 the last of this 
