MICROSCOPIC DRAWING AND ENGRAVING. 
body of the insect. The length of the eggs varies from the 40th to 
the 50th of an inch. 
In the larva (fig. 1) the obvious and curious parts are the 
kidney-shaped bodies, b and d , two of which are situated near the 
Fig. 36. 
head, and the other two in the third division from the lower 
extremity. The first pair are inclined towards each other, while 
the others lie in parallel planes, as represented in the plan, or 
bird’s-eye view,'drawn of the natural size in fig. 3. ^ Physiologists 
have not ascertained what may be the functions, performed by 
these singular organs : it is worthy of remark, however, that a 
similar structure is observable in the tadpole, and figured in 
Sir Everard Home’s Lectures on Comparative Anatomy. The other 
parts of its structure, which appear equally singular and curious, 
are a number of globules, a , which are situated near the first 
pair of bodies, 5. These globules have a slight oscillatory motion 
in different directions, and, like the reniform bodies, seem to 
have a metallic lustre, but are not opaque. From the exquisite 
polish of these globules, they reflect the forms of surrounding 
objects, as window-bars, &c., which are indicated in the drawing 
by small squares, resembling the images formed by convex 
mirrors. 
When the larva, as shown of the full size in fig. 3, is examined 
from above, it exhibits the position and decussation of the various 
muscles lying along the back, which are observed to cross at the 
joints, and at points situate midway between them. 
The alimentary canal appears to contain some particles of a 
pinkish coloured matter: but every part of the object, as seen 
beneath the microscope, is so accurately noted in the drawing, that 
a more minute description must be deemed superfluous. 
If the insect have a sufficient supply of food, it only continues 
for a few weeks in the larva state, when it rapidly changes to the 
pupa, shown in the drawing (fig. 2). When it is desirable to 
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