146 STATES OF INSECTS. (Larva.) 
is quite unknown: Goedart fancies that they secrete a 
potent poison, and are intended as instruments of defence; 
but both suppositions are altogether unfounded. It has 
been remarked, that the body of those caterpillars which 
have these horns, is firmer, and yields less to the touch 
than that of those which have no such appendages?. ‘The 
larva of a small timber-devouring beetle (Hylecactus der- 
mestoides) has, like the above caterpillars, a long horn, 
and in the same situation: it has also a singular protu- 
tuberance on the first segment®. Upon some other 
caterpillars, as Laszocampa ? Stigma, a singular pair of 
horn-like appendages arises from the back of the second 
segment of the body, excluding the head. In a tawny- 
coloured one from Georgia, with a transverse row of 
short black spines on each segment, these horns are half 
an inch long, black, covered with spinous eminences, 
rather thickest at the base, and terminate in a little knob. 
They appear to articulate with the body at the lower 
extremity. I have another species, black, with narrow 
longitudinal yellow stripes, in which these horns are of 
equal thickness at base and apex, but with the same ter- 
minal knob. Danais Archippus has a pair of tentacula 
at the head, and another pair, but shorter, at the tail; 
and D. Gylippus has, besides these, two in the middle 
of the body *. 
Weare equally ignorant of the use of the upright horn 
found upon the back of the fourth segment in the larva 
of some moths (Acronycta Psi, and tridens), which is of 
a construction quite different from that of those last 
* N. Dict. d’ Hist. Nat. vi. 252. 
» Schellenberg Entomolog. Beytr. t. 1. 
° Smith’s Abbott's Insects of Georgia, t. xiii. 
= eS Se 
