STATE AGRICULTURAL SOCIETY. 
843 
ELM. LEAVES. 
of its wing-covers and a small oblong spot near their base, though 
originally named by Linnaeus from a small seaport town of Sweden, is 
common over the chief part of Europe, feeding upon the leaves of the elm, 
to which it is sometimes very destructive. It has been introduced from 
thence into this country, and on its first appearance in the city of Balti¬ 
more some twenty years ago, it and its larvae, which are thick cylindical 
blackish six-footed grubs, wholly denuded the elms of their leaves, for 
several successive seasons. 
The following incident, verbally communicated to me by the Rev. Jolm Gr. 
Morris, D. D., of Baltimore, merits to be related in this connection.it being 
one of the prominent popular errors prevailing in our country with respect 
to insects, to regard them as a unit, all alike in their nature and habits, 
and hence, if a remedy is discovered to be efficacious against one particu¬ 
lar insect, the experimenter at once concludes, with the fullest confidence, 
that it will be similarly efficacious against all other insects. 
Soon after this beetle commenced its destructive career in Baltimore, a 
representation of the evil was communicated to one of the most eminent 
and justly distinguished men of science in our country, with a request that 
he would inform them of some remedy for it. He, not being versed in this 
particular branch of Natural History, inferred the insect to be the Canker 
worm, which had not long before made very similar havoc upon the elms 
in his own neighborhood ; and he accordingly replied, informing them that 
if they would surround the trunks of their trees with collar-like troughs 
and keep these filled with fish-oil, he doubted not they would find it an 
effectual remedy. With much care and at some expense this measure, 
coming from such a respectable source, was extensively resorted to. But 
they soon learned that what is sauce for the goose is not always sauce for the 
gander, or in other words, that what is an effectual remedy for one insect 
on elms is not equally efficacious for all other insects upon the same tree. 
As some had predicted who had informed themselves of the habits of this 
beetle, the protected trees received not the slightest benefit from this 
measure. 
The Grape-vine flea-beetle, §128, a very small greenish-blue or 
purple jumping beetle, and the Goldsmitii-beetle, §57, a large shining 
lemon yellow beetle, also inhabit the elm, eating the leaves. 
347. Elm gall-louse, Byrsocrypta Vlmicola, new species. (Homoptera. Aphidce.) 
In June, an excrescence or follicle like a cock’s comb, arising abruptly 
from the upper surface of the leaf, usually about an inch long and a quarter 
of an inch high, compressed and its sides wrinkled perpendicularly and its 
summit irregularly gashed and toothed, of a paler green color than the leaf 
and more or less red on the side exposed to the sun ; opening on the under 
side of the leaf by a long slit-like orifice ; inside wrinkled perpendicularly 
iuto deep plaits and occupied by one female and a number of her young, 
Eomeof which are often strolling outside upon the under surface of the leaf. 
