STATES OF INSECTS. (Larva.) 145 
&e.; which, though not properly coming either under 
any of the above parts, or under the clothing of these 
animals, yet require to be noticed. Upon these I shall 
now enlarge a little. 
You must have observed upon the back of the last 
segment but one of the caterpillar of the silk-worm a 
horn-like process, rising at first nearly perpendicularly, 
and then bending forward. A similar horn, though con- 
- fined in the family of Bombycide to the silk-worm and 
a few others, if we may believe Madame Merian, who, 
however, often makes great mistakes, is found in the 
beautiful caterpillar of one of the largest and finest moths 
that we know (Lrebus Strix), the glory of the Noctuide : 
it is present also in most of those of the hawk-moths?, in 
the same situation, but is much longer*, and commonly 
curving backwards over the tail?. Sometimes however, 
as in Smerinthus ocellatus and Mucroglossa Stellatarum, 
it is perfectly straight. ‘These organs towards the apex 
are horny, and often end in a sharp point; nearer the 
base they are fleshy. They are without any true joint‘, 
yet the insect can elevate or depress them at pleasure. 
Under a lens, they usually appear covered with spinous 
eminences, arranged like scales. The use of these horns 
® Merian Ins. Sur. t. xx. 
> Deilephila Porcellus, Vitis, &c., form an exception to this rule. 
In Sphine Labrusce (Merian Ins. Sur. t. xxxiv.) this anal horn is 
replaced by a gibbesity, in Macroglossa 2nothere by a callous eye- 
like plate. Perhaps in some of these cases the caterpillar may have 
been only seen after its last moult, when it is said to cast this horn ; 
but this is a point that requires further investigation. 
* [ have a caterpillar, I believe from Georgia, in which this horn 
is nearly an inch long, filiform, slender, and tortuous. 
4 Prare XVIII. Fie. 12. c. 
* That of Sphinx Iatrophe appears to be jointed, at least it is 
moniliform. Merian Surinam. t. xxxviii. Compare also ¢. ili. 
VOL. III. L 
