HOP-FLY. 
73 
are viviparous, and that without the usual union of 
the sexes, and so are their children and grandchildren. 
— the number of births depending solely on the quantity 
and quality of their food : at last, as winter approaches, 
the whole generation, or series of generations, assumes 
wings, which the parents did not possess, undergoes 
frequently a change in colour, and instead of being vivi- 
parous, lays eggs. 
To this singular tribe belongs the Hop-Fly, an insect 
and its stump runs very near the third vein. 6lh. The second vein is forked 
at its tip. 7th. The second vein is wanting, except near its source. 8th. A 
third fork is sent forth with the second. 9th. Both branches of the second fork 
cease soon after their source. 10th. One branch of the second fork is wanting, 
except at its tip. 
The Viviparous Wingless Female of the third Generation. — This is very dif- 
ferent from that of the first generation, being much smaller, narrower, paler, and 
more flat; the body is long-elliptical or spindle-shaped, when young it is greenish- 
white, and half transparent ; the limbs are white ; the antennas are a little 
more than half the length of the body ; the eyes are black ; the tubes are about 
one-fifth of the length of the body, when full grown it is a little broader, and 
of a grass-green colour ; the tarsi and the tips of the antennae, of the mouth, 
of the tubes, and of the tibiae are black ; the horns on the front and the projec- 
tions on the first joints of the antennae are still more developed than in the 
first generation ; the tubes are cylindrical, and of an equal thickness through- 
out. 
\st Variety. — The antennae, excepting the base, are black. 
2nd Variety. — The body is pale green, with interrupted, darker green bands. 
It is not so prolific as is the first generation, but far more numerous : the body 
is narrower when it feeds on the hop than when on the sloe, where I have 
found it in the middle of July, and it sometimes occurs there in great profusion 
towards the end of that month, and is accompanied by the winged female, and 
also by the pupa of the fourth generation, whose horns on the front are more 
developed than when it acquires wings, but less so than those of the wingless 
female. The third generation on the sloe is sometimes infested by the little 
red Acarus, Leptus Aphidum, and occasionally great numbers of Formica rufa 
come to feed on its honey. Length of the body f — 1 line ; of the wings 
2^— 2f lines.— jP. Walker. 
