MICROSCOPIC DRAWING AND ENGRAVING. 
generally straight, curves itself in the shape of fhe letter S when 
the creature seizes its prey. During the summer the larva is said 
to attain its full size in about fifteen days, when it quits the 
water and creeps into the neighbouring earth, where it forms with 
considerable skill a round cell, in which, in about five days, it 
changes to a pupa of a whitish colour, with two obtuse points at 
the extremity of the body. In about a fortnight or three weeks it 
issues as a perfect beetle. If, however, the change to the pupa 
state take place in the autumn, the creature does not pass into the 
form of a perfect insect until the following spring. 
The beetle is at first soft and yellowish, but soon hardens and 
assumes a darker colour. It is not, however, until the end of 
eight days, that it has acquired its proper consistency.* 
Dr. Goring, in describing the specimen from which the drawing 
was taken, says that the three first segments of the body, com¬ 
mencing from the neck, contain a bundle of nerves, terminating 
with three loops, which are very perceptible in the young larva, 
being of a colour more brilliant than the other parts of the body. 
They are shown in the figure like a bundle of strings or cords, 
extending from the centre of the head to the extremity of the 
third joint of the body. 
The two large tracheae, commencing from the head, attain 
their greatest development about the third joint of the body. 
They follow the sides of the body to a point near its extremity, 
where they coalesce and terminate. These air-tubes, in their 
passage along the body, throw out numerous ramifications, which 
are shown in the figure. These tracheae are four in number, two 
interior and two exterior. The interior ones commence at the 
ganglion, which terminates at the third joint of the body, and 
they disappear at the third joint from the tail. In the last joint 
but one is situated the organ of pulsation. 
58. Dr. Goring has also left two very beautiful engravings of 
the larva and the pupa of the gnat, taken from a specimen of the 
species called tipula crystallina of De Geer, the chironomus 
plumicornis of Fabricius, and the corethra plumicornis of 
Stephens. I have reproduced these beautiful objects from Dr. 
Goring’s engravings, the larva being represented in fig. 1, the 
pupa in fig. 2, and a plan, or bird’s-eye view of the larva, in its 
natural size, in fig. 3. 
The gnat, of which these are the previous forms, is represented 
in fig. 36, the drawing having been taken while the creature was 
in the act of laying the cluster of eggs figured on the right side. 
The short line between the figures gives the real length of the 
* Westwood on “Insects,” yob i., p. 95. 
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