Scientific American Supplement, No. 447, July 26, 1884Various
Science
Scientific American Supplement, No. 447, July 26, 1884
Various
Science -- Periodicals
At the last meeting of the New York Microscopical Society, a paper
was read by Dr. Samuel Lockwood, secretary of the New Jersey State
Microscopical Society. His subject was the Wine Fly, _Drosophila
ampelophila_. The paper was a contribution to the life-history of this
minute insect. He had given in part three years to its study, beginning
in September, 1881, when nothing whatever of its life-history seemed to
have been known. In October the flies attacked his Concords. He found
upon a grape which he was inspecting with a pocket-lens an extremely
small white egg; but lost it. The grapes when brought on the table were
infested by the flies, which proved to be the above mentioned species.
When driven from the grapes they would fly to the window, where he
captured two of them These were placed in a jar with a grape for food.
In two days he found one egg on the outer skin of the grape. The laying
was kept up for four or five days, until there were about thirty, some
on the outside of the grape and some at an opening where the two flies
had fed. The egg had a pair of curious suspenders near the end where
the mouth of the larva would develop. These suspenders were attached at
their ends to the grape, but where the egg was laid in the soft part of
the fruit the suspenders were spread out at the surface; thus the larva
would emerge clean from the shell. The egg was 0.5 mm. in length, and
about a fourth of that in width. The larva when grown was at least four
times as long as the egg. As the larva burrowed in the juices of the
fruit, two quite prominent breathing tubes at the posterior end were
kept in the air. Between these cardinal tubes were several teat-like
points, much smaller, but having a similar function.
The larvae appeared in five days after the eggs were laid. In about as
many more days the puparium state would be entered, and in about six
days more the fly or imago would appear. In ovipositing the suspensors
would leave the oviparous duct last. The paper claimed that the curious
shape of the egg compelled the female to oviposit slowly, as it took
time for the egg to assume its form; hence, the eggs were not laid in
strings or masses, but singly and at considerable intervals.
Public-domain text, read in full here on John Shaqi.
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