saria, found on the leaves of the black poplar, 
and causing them to take the form of a purse, is 
of a. dull brown colour, somewhat translucent ; 
its sides are gibbous; and its ears are short.—The 
aspen blight-bug, Hriosoma populi, found.on the 
rolled leaves of the aspen tree, is diversified in 
colour; its head and its corselet are black ; its 
abdomen is greenish; and its wings are white, 
with the outer margin black.—The nettle blight- 
bug, Hriosoma urtice, found on the stems and 
| leaves of the common nettle, has a prevailingly 
_ black colour ; its abdomen exhibits a brazen hue ; 
_ its wings are white, with parallel black veins; its 
wing-rib is brown; its legs are black ; and its tail 
_ has an abrupt bristle-—The principal other well- 
_ defined aphides of the blight-bug or eriosoma 
_ division, are the hawthorn blight-bug, compara- 
_ tively small, discharging a profusion of honey 
dew, and inhabiting the shoots and young leaves 
of hawthorn plants; the beech blight-bug, inhab- 
iting the leaves of the beech tree; the spruce 
blight-bug, inhabiting the branches of the spruce 
_ fir; the elm blight-bug, inhabiting the rolled 
leaves of the elm; and the honeysuckle blight- 
bug, inhabiting the honeysuckle plant. 
The aphides, in their economy of pairing and 
reproduction, are the most remarkable animals 
yet known. Bonnet, Bazin, Reaumur, Trembley, 
| Lyonnet, and other naturalists, ascertained, by 
_ experiment and observation, some facts in this 
_ economy so wonderful as to be utterly incredible 
except on high and complicated authority. Bon- 
net selected a plant-louse which he had seen born 
the instant before of a mother without wings, 
and placed it upon a leafy spindle-tree branch, 
which he had carefully and minutely ascertained 
_ to be free from the presence of any other indivi- 
| dual aphis. He fixed the branch with the insect 
in a phial of water, placed the phial in a garden- 
pot of mould, covered the whole with a glass ves- 
sel, and so completely buried the edges of the 
vessel in the mould that there could not possibly 
be any communication between the imprisoned 
insect and the external world. He commenced 
his experiment on the 20th of May; and day after 
| day, he hourly, from five in the morning till nine 
or ten at night, watched the insect with a mag- 
| nifying glass; and he found that it four times 
changed its skin, and grew like a caterpillar, that 
on the Ist of June it produced a living young 
| insect, and that, from that date till the 22d of 
_the same month, it brought forth ninety-five 
young insects. Bazin made similar experiments 
and observations upon the poppy plant-louse and 
the rose plant-louse, and found them also to pro- 
duce progenies of young without having paired. 
Trembley put an elder-tree plant-louse on a slip 
_ of elder, enclosed this in a glass tube, plunged 
one end of the tube in water and plugged the 
_ other with cotton, and found the insect about 
_ two months after beginning to produce young, 
_ and subsequently producing more at intervals 
according to the temperature of the atmosphere. 
APHIS. 
Trembley’s breeding apparatus is shown in Fig. 
15, Plate XVI, Reaumur’s in /%g. 16. Bonnet, not 
contented with his first experiments, instituted 
a new series, and ascertained that at least five | 
generations of the elder-tree plant-louse, and no | 
fewer than nine generations of the oak plant- 
louse, may be produced without any pairing. 
Lyonnet afterwards confirmed these ulterior ob- | 
servations of Bonnet; and Duvan observed some | 
individual plant-lice during seven consecutive | 
months, and found eleven generations to be pro- | 
duced without pairing. This extraordinary and 
truly wonderful fecundity of female aphides, how- | 
ever, becomes exhausted ; and pairing becomes as 
indispensable for its renewal as it is for the re- 
production of any other animal. Yet the female, 
after having paired, does not produce living 
young but eggs or a kind of pupz resembling | 
egos; the insects evolved from the eggs produce 
living young ones without pairing ; allthe young 
of successive generations till the approach of 
pairing time are females; and:in autumn or at 
the close of summer, when fecundity is exhausted 
and pairing becomes necessary for its renewal, | 
some males are produced. How mighty and glori- | 
ous are the evidences of the Divine skill and super- | 
intendence throughout each of the infinite diver- | 
sities of organism and economy among creatures! | 
The rapidity with which the aphides multiply — 
is almost as astonishing as their peculiar mode 
of generation. 
Calculating on the data of Bon-— 
net’s observations, reckoning 90 for the first gen- 
eration from a single mother, and supposing that | 
each individual will be equally prolific with the 
parent, the second generation will amount to — 
8,100, the third to 729,000, the fourth to 65,610,000, | 
the fifth to 5,904,900,000, and the ninth to | 
350,970,489,000,000,000. Yet several naturalists | 
estimate the increase at considerably greater 
rates; and Dr. Richardson, in particular, cal- 
culates the ninth generation to amount to 
25,065,093,750,000,000,000, and does not include | 
in this number the generation of pups immedi- 
ately before winter for the renewal of the race or 
progeny of the following season. Major records 
that, in September, 1829, he saw swarms of the 
apple bug-blight alighting in clouds, and cover- 
ing every kind of tree or plant within the space 
on which they alighted; and White of Selborne 
says, “On the first of August, about halfan-hour | 
after three in the afternoon, the people of Sel- 
borne were surprised by a shower .of aphides 
which fell in these parts. 
covered with these insects, which settled also 
on the trees and gardens, and blackened all the 
vegetables where they alighted. These armies, | 
no doubt, were then in a state of emigration, and 
shifting their quarters, and might perhaps come 
from the great hop plantations of Kent’and Sus- 
sex; the wind being that day at north. They 
were observed at the same time at Farnham and 
all along the vale at Alton.” 
They who were walk- | 
ing the streets at that time found themselves | 
