452 
ANNUAL REPORT OP NEW YORK 
HOP-APniS. DESTROYED BY OTHER INSECTS. 
and on a sudden alteration of the weather we have known them perish by myr¬ 
iads in a night. This was especially exemplified in the Farnham district, 
about the middle of June 184G, which suddenly recovered from a most severe 
attack, and afterwards produced the largest crop ever known in that quarter. 
The condition of the plant, therefore, is never hopeless, however severe the 
attack may be, provided there is time for it to put forth its lateral or fructify¬ 
ing branches. We know also several instances in East Kent which occurred in 
the same year, when the planters sold their own growths* on the poles at a few 
shillings per acre, and these same plantations so far recovered that many of 
them afterwards produced a crop worth from thirty to fifty pounds per acre. 
‘ ‘ The progress and usual termination of the aphis blight may be thus de¬ 
scribed. The flies, as before remarked, on their first arrival, immediately 
suck the under side of the upper small leaves of the bine, and thus they there 
deposit their young, upon the most succulent part of the plant. The multipli¬ 
cation of the lice is so rapid, that the leaves become so thickly covered as 
scarcely to allow a pin to be thrust between them. They quickly abstract the 
juices of the bine, so that the leaves assume a sickly brown hue, and curl up, 
and the bine itself ceases to grow and falls from the pole, the lice continuing 
till they perish for want of food; and thus, without the intervention of a 
favorable change, the crop is destroyed, and the grower may often consider 
himself as fortunate if the plant recovers a due amount of vitality to produce a 
crop in the following year, for occasionally the hills are killed by the severity 
of the attack. This description of course, applies only to the most severe and 
unusual blights.” 
The Aphides are the most evanescent of all insects. They spring up 
suddenly, in such immense numbers as to threaten the utter destruction of 
the vegetation on which they subsist, and ere long they vanish with equal 
suddenness—sometimes continuing but a few weeks, and rarely remaining 
in force longer than through one year. It thus appears, that, so long as 
the atmospherical or other influence which favors their increase, continues 
to operate upon them, they thrive and prosper, and when this influence 
passes away they rapidly decline. 
The decline and disappearance of these plant-lice is greatly expedited by 
other insects which destroy them; and in many instances it appears to be 
to these destroyers rather than to any atmospherical change, that the vege¬ 
tation on which they abound becomes so suddenly released from them. No 
other tribe of insects has so many enemies of its own class as the plant- 
lice. The different species of Coccinella or lady-bugs which are every¬ 
where so common, live exclusively upon the Aphides, as do also the larvas 
of the two-winged Syrphus flies and the four-winged Golden-eyed flies. 
Snperadded to these destroyers the plant lice also have their internal para¬ 
sites — exceedingly minute worms or maggots residing within their bodies 
and feeding upon till they kill them. Thus, whenever a tree or shrub 
becomes thronged with plant-lice, these destroyers gather among and 
around them, in rapidly augmenting numbers, and subsist upon them until 
they have wholly exterminated them. Kirby and Spence (page 187) state 
that in the year 1807 the sea shore at Brighton and all the watering places 
on the south coast of England, was literally covered with lady-bugs, to the 
