144 Twenty-third Report ox the State Cabiset. 



day the tliiimb could not be bent without experiencing a sensible 

 degree of pain, which was materially increased by an attempt to bring 

 the joints to a right angle. This stiffness of the joint continued for 

 four days. When the blotches subsided, small purplish spots of coagu- 

 lated blood appeared in their place, which by degrees became more 

 circumscribed, until after the lapse of a few days, when they presented 

 an appearance similar to that of grains of gunpowder burned beneath 

 the skin. These gradually disappeared ; those nearer the surface by a 

 scaling of the skin above them ; those deeper, removed by the slower 

 process of absorption, were visible at least two weeks. 



When the larva was permitted to fall upon the thicker skin of the 

 palm of the hand, a slight stinging sensation was experienced, and minute 

 purple dots were developed, continuing a shorter time than the above. 



The sting is doubtless the result, not of broken tips of the spines 

 remaining in the flesh — for none such could be observed by careful 

 scrutiny with a lens — but of a poison secreted by the larva, and prob- 

 ably injected through a minute aperture in the tip of the spine. 

 Whether its excretion is voluntary or involuntary was not determined, 

 it not having occurred to institute the simple experiment by which 

 that point could readily have been ascertained. A slight motion of the 

 larva, apparently a contractile one, was frequently observed to accom- 

 pany the sting ; but this may have been either defensive, or simply the 

 consequence of alarm at being rudely touched. 



Some tips of the spines clipped off and placed between slides under 

 a high magnifying power, showed, under varying pressure, a motion of 

 a fluid within them ; but no apical opening could be discovered for its 

 escape. 



The ability to inflict a sting does not belong to all the spines of the 

 larva, but only to those of the two subdorsal rows on segments three 

 to ten, and the dorsal spine on segment eleven. These differ from 

 those elsewhere on the body in their fascicular arrangement, their 

 shorter length, the regular taper of the branches, and their tawny 

 color, as appears in detail in the description given of the mature larva. 

 With this interesting structural peculiarity in mind, the larva may be 

 handled wuth impunity, as was repeatedly done with the fifty or more 

 individuals composing the colony from which these notes were drawn, 

 in the frequent transfers which they required as they approached 

 maturity, to fresh food and cleansed quarters. With proper care, 

 the thumb and fingers could safely be passed along their sides and 

 beneath them, slowly raising them from the leaf or stem to which they 

 were attached ; but if attempted too hastily, the larva throws itself in a 

 circle, projects its defensive armor, and inilicts a sting which eftectually 

 releases it from the grasp. 



