[From Proc. of the Entomological Society of Washington, Vol II., No. i, 1891.] 
ON THE DIFFICULTY OF DEALING WITH 
LACHNOSTERNA. 
Prof. C. V. Riley. 
Mr. Smith’s studies, supplementing as they did Dr. Horn’s, 
had resulted in the separation of the old form fusca into sev- 
eral species, which appeared more or less in succession, so 
that for a considerable period one or another species would be OF WASHINGTON. 
59 
present. I have recently been much interested in the attacks 
of these beetles on certain large trees, between thirty and forty 
feet high, which I transplanted last February to my new 
home, Sunbury, on Washington Heights. The trees specially 
attacked were a swamp oak and a chestnut, both of these trees 
being on the west of my residence. It so happens that the 
ground on the east was largely filled-in or made ground, while 
that on the west was, on the contrary, simply leveled off. This 
proved to be badly infested with Lachnosterna, and I have 
had great difficulty in preventing the entire defoliation of the 
two trees mentioned. The first species to appear was L. hir- 
ticula, and this was by far the most abundant and injurious 
species—the only other species noticed being fusca. It was 
evident from the beginning that the trees in question could not 
withstand the combined check resulting from the transplant- 
ing and the defoliation by the insects, so that I made strenu- 
ous efforts to thwart the latter. Smudges doubtless 
have been efficacious if they could have been employed, but 
they were rendered impracticable owing, first, to the height of 
the trees and then to the prevalence of winds. With the assist- 
ance of Mr. Marlatt I made various experiments with insecti- 
cides, the chief of which were as follows : 
(1) The trees were sprayed with a strong whale oil and 
tobacco soap solution about five o’clock in the evening. The 
spraying was satisfactorily and thoroughly done by means of 
the bamboo extension rod. A rain which followed during the 
night somewhat interfered with the experiment, but not until 
after the beetles had appeared and cut off a quantity of 
the leaves—showing the practical inutility of the appli- 
cation. 
(2) London purple was applied at the rate of one pound to 
one hundred and twenty-five gallons of water, a stronger mix- 
ture not being advisable, owing to the tender character of the 
foliage, especially of the oak. This application was also 
satisfactorily and thoroughly made, not a leaf having escaped 
the spraying. There is no doubt but that this spraying 
resulted in the destroying of a considerable number of beetles, 
since two dead ones were found under the oak tree next day. 
It did not, however, limit the onslaught, and I made up my 
mind that it would be futile to endeavor to prevent the attacks 
of the beetle by any insecticide or other means at command, 
for the simple reason that the beetles would escape nightly 
from the soil, swarming more or less numerously around these 
two trees. 
(3) I also endeavored to attract the beetles by lamps float- 
ing in a tub of water having a scum of kerosene. The num- ENTOMOLOGICAL SOCIETY 
ber so attracted was so few in comparison with those that 
swarmed to the trees, that I have been led to reverse my 
opinion as to the value of this mode of destroying the beetles. 
The experience has a certain value, and I would draw the 
following conclusions from it : 
First. That it is impossible to protect large and tall trees 
from these beetles, when, as in this instance, these are issuing 
in large quantities from the ground immediately under and 
around the trees. 
Secondly. It confirms the fact that these insects, as do so 
many other species, show a predilection for newly transplanted 
trees, in which the growth is less vigorous and the foliage 
more tender than it is in healthy forest trees. 
Thirdly. My place is well isolated from other forest trees, 
the nearest woods being nearly half a mile away, with no other 
cultivated trees of consequence in the immediate vicinity. It 
occurred to me, therefore, that my trees suffered from a con- 
centration of the beetles from other parts of the neighborhood 
on to these isolated trees, but I became convinced that such 
was not the case, but that they all came from the ground in 
the immediate vicinity. This conclusion was emphasized by 
the fact that another large oak not two hundred feet away, 
but on the east side of the house, and in ground from which no 
beetles issued, was scarcely touched. The practical inference 
is that if we can keep the ground in the immediate vicinity of 
our trees free from the larvae, little injury will be suffered 
from the beetles. 
The injury was not done through devouring of the leaves, 
but almost entirely through the gnawing of the petiole near 
the base or junction with the twig, the ground being covered 
each morning with fresh leaves, 95 per cent, of which had 
hardly been eaten at all. This preference for the gnawing of 
the petiole is, so far as I am aware, a new experience, and may 
be one of the habits peculiar to hirticula. It is an interesting 
point, which, I regret, time did not permit me to solve satis- 
factorily, whether the same beetles re-enter the ground and 
re-visit the tree day after day, or whether, on the contrary, 
they are short-lived, and, after their first nocturnal havoc, 
pair and re-enter the ground only to propagate. The ap- 
pearance of fresh holes daily would indicate the latter alter- 
native, and I am inclined to believe that the injury was done 
by a succession of beetles, and also by a succession of species, 
as it continued for the period of nearly a month, gradually 
diminishing, however, and being worst during the first few 
nights and especially in warm and calm weather.