THE SYRPHIAXS. 
609 
slender bristles. They live on the honey of flowers. The 
last joint of their short antennae bears a bristle, which is 
sometimes feathered. Their heads are large and hemi- 
spherical. Many of these flies are often mistaken for bees 
or wasps, and some of them lay their eggs in the nests of 
the insects they so closely resemble. Others drop their 
eggs among plant-lice, which their young afterwards destroy 
in great numbers. The larvae of a few are aquatic, and arc 
provided with very long, tubular tails, through which they 
breathe, and have been called rat-tailed maggots. Some of 
the largest and most beautiful of these flies live, in the 
maggot state, in rotten wood. One of these rat-tailed flies 
is often seen on windows, in the autumn. It flies with a 
buzzing noise. Its eyes are very large, and of a bright 
copper-color ; its body is brassy green ; and there are five 
gray stripes on the thorax. It measures about four tenths 
of an inch in length. It is the 
Eristalis sincerus 6 of my Cata- 
logue. The Milesia excentrica 7 
(Fig. 267), named in the same 
work, strikingly resembles a hornet; 
its hind body being banded with 
black and yellow in the same way. 
Its head and thorax arc black, the former margined around 
[0 Eristalis sincerus, Harris, is identical with E. ceneus, Linn., so common in 
Europe. — Osten Sacken.J 
[ t The description of this species is too short to have a scientific value. In 
order to prevent its being superseded by a subsequent description, under some 
other name, I subjoin a full description. 
Milesia excentrica , Harris. Thorace nigro, fiavomaculato, scutello ccneo; a'o- 
domino flnvo, nigro fasciatoj pedibus fulvis; tibiis, tarsisque anticis nigris; 
Length, to inch. 
Male : Ilypostoma golden-yellow, sericeous, with a shining black stripe in the 
middle. Antenna pale ferruginous; the space between the eyes has the form of a 
triangle, which is golden-yellow at the tip, and black on the vertex. The hind 
part of the head is sericeous, yellow along the borders. Thorax black ; a yellow 
spot on the shoulder, another behind it, from which runs a narrow groove, yellow 
at the bottom; a third yellow, elongated spot, pointed upwards, near the corner of 
the scutollum. A gray stripe runs along the middle of the thorax; it becomes 
very faint beyond the centre aud ends in a triangular yellowish spot near the scu- 
77 
