146 STATES OF INSECTS. 



commonly curving backwards over the tail 3 . Some- 

 times, however, as in S. ocellata and S. 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 b , yet 

 the insect can elevate or depress them at pleasure. Un- 

 der a lens, they usually appear covered with spinous emi- 

 nences, arranged like scales. The use of these horns is 

 quite unknown : Goedart fancies that they secrete a po- 

 tent 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 c . The 

 larva of a small timber-devouring beetle {Lymexylon der- 

 mestoidesF.) has, like the above caterpillars, a long horn, 

 and in the same situation : it has also a singular protu- 

 berance on the first segment d . Upon some other cater- 

 pillars, as mBombyx Stigma F., 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 



a Plate XVIII. Fig. 12. c. 



b That of Sphinx latrophce L. appears to be jointed, at least it is 

 moniliform. Merian Surinam, t. xxxviii. Compare also t. iii. 

 N, Diet. d'Hist. Nat. vi. 252. 

 d Schellenberg Entomolog. Beytr. t. 1. 



