ere are already
over thirty North American species of this genus described in various
works. Few insects live in the sea, but along the coast of New England
a small, slender white larva (Fig. 63a, magnified, and head greatly
enlarged; Fig. 64, pupa and fore foot of larva, showing the hooks),
whose body is no thicker than a knitting needle, lives between tides,
and has even been dredged at a depth of over a hundred feet, which
transforms into a yellow mosquito-like fly (Fig. 65, with head of the
female, magnified) which swarms in summer in immense numbers. I have
called it provisionally Chironomus oceanicus, or Ocean gnat. The larvae
of other species have been found by Mr. S. I. Smith living at great
depths in our Northern lakes. These kinds of gnats are usually seen
early in spring hovering in swarms in mid air.

[Illustration: 65. Ocean Gnat.]

[Illustration: 63. Larva of Ocean Gnat.]

[Illustration: 64. Pupa of Ocean Gnat.]

The strange fact has been discovered by Grimm, a Russian naturalist,
that the pupa of a feathered gnat is capable of laying eggs which
produce young during the summer time. Previous to this it had been
discovered that a larva of a gnat (Fig. 66 _a_, eggs from which the
young are produced) which lives under the bark of trees in Europe, also
produced young born alive.

The Hessian fly (Fig. 67, _a_, larva; _b_ pupa; _c_, stalk of wheat
injured by larvae) and Wheat midge, which are allied to the mosquito, are
briefly referred to in the calendar, so that we pass over these to
consider another pest of our forests and prairies.

[Illustration: 66. Viviparous gall larva.]

[Illustration: 67. Hessian Fly and its Young.]

The Black fly is even a more formidable pest than the mosquito. In the
northern, subarctic regions, it opposes a barrier against travel. The
Labrador fisherman spends his summer on the sea shore, scarcely daring
to penetrate the interior on account of the swarms of these flies.
During a summer residence on this coast, we sailed up the Esquimaux
river for six or eight miles, spending a few hours at a house situated
on the bank. The day was warm and but little wind blowing, and the
swarms of black flies were absolutely terrific. In vain we frantically
waved our net among them, allured by some rare moth; after making a few
desperate charges in the face of the thronging pests, we had to retire
to the house, where the windows actually swarmed with them; but here
they would fly in our