54 INTERNAL ANATOMY OF INSECTS. 
gan it has four respiratory horns in the trunk near the . 
head*. 
The larva of the chameeleon-fly (Stratyomis Chameleon) 
is furnished with a respiratory organ of a still different 
and more elegant structure, exhibiting some resemblance 
to the ¢entacula of what are called sea anemonies. In 
this larva the last joint of the body is extremely long, 
and terminates in an orifice to receive the air, which is 
surrounded by a circle of about thirty diverging rays, 
consisting of beautifully feathered hairs or plumes. This 
apparatus serves the same purpose with that above de- 
scribed of the larva of the gnat. ‘The feathery hairs are 
so prepared as to repel the water, and thus to suspend 
the animal by its tail at the surface, and preserve a con- 
stant access of air. When it has occasion to sink, it 
turns these hairs in and shuts the orifice, carrying down 
with it an air-bubble that shines like quicksilver, and 
which Swammerdam conjectures enables it again to be- 
come buoyant when it wants to breathe. 
In the red aquatic larva of a small gnat (Chironomus 
plumosus) there are two anal respiratory subcylindrical 
horns, with the orifice fringed with hairs¢; and in an- 
other gnat ( Tipula annulata L.)Reaumur discovered four. 
The larva of Tanypus maculatus, whose remarkable legs 
I formerly noticed‘, exhibits in the interior of its trunk 
two long, oval, opaque bodies, which De Geer conjec- 
tures may be air-reservoirs ; these, when the animal as- 
sumes the pupa, according to every appearance become 
external, and are placed on the back, precisely where the 
* Reaum. iv. 456. ¢. xxxi. f. 1—7. BSPLATE XIN. Pie. 1S. w. 
© Bibl, Nat. ii. 44. “ Pirate XIX. Fre. 10. a. 
© Reaum. iv. ¢. iv. f. 6. s, u. Noe 23 
