402 TRANSFORMATIONS OF INSECTS. 
thorax and to the abdominal segments. The bodies of the larve 
are not supplied with any respiratory apparatus on their sides, so 
that the insects can only breathe by elongating and sticking up 
their tails, which are perforated, and can act as breathing organs. 
The larve are found in very briny waters, and even in the water of 
salt works, and besides in stinking pools. The perfect insect of this 
rat-tailed creature has a large black body, with russet spots upon 
the abdomen. 
In the engraving on page 401 the larvae may be seen having 
two large eyes, a stoutish body, and a long tail. 
If one of them be placed in pure water it will live for a short 
time, and by just covering the insect at first, and adding water 
gradually, the tail will be noticed to become erect, and to elongate 
gradually, so as to keep pace with the flow of water, and always 
to remain above the surface. After having developed its tail 
to the utmost, should any more water be added the insect is 
drowned. 
The Syrphus Fly, or Aphis Eater, is gaily spotted and banded 
with yellow, so that it resembles a small wasp. They may be seen 
upon flowers in fine weather, and they lay their eggs upen bushes 
and plants. The larve are very small creatures, and are very 
slender in front, and they walk, or rather crawl over the foliage, 
principally with the aid of their mandibles. 
They are of a pale green colour, and may often be observed 
upon rose trees, where they feed upon the plant lice, which they 
suck and destroy with great rapidity. The larve of other 
Syrphide even attack caterpillars, and manage to eat their way 
into the bodies of their victims, but they always leave the last 
segment of the body in the open air, so as to breathe, for the 
respiratory orifices are situated at the end. 
The true flies, or Mzuscide, are a great puzzle to those na- 
turalists who indulge in classification. They have a distinct 
proboscis, which is thick, membranous, and terminated by two large 
lobes. It is formed by the united mouth-pieces, and especially by 
the large lower lip, and the mandibles, which are partly united 
together, form a sharp blade. These Diptera, which differ so much 
in the adult stage, resemble each other in the larval condition. 
The white maggots are so well known that it is not necessary to 
