Packard.] RELATTOXS OF INSECTS TO MAT^. 87 



the skin. These gradually disappeared ; those nearer the 

 surface by a scaling of the skin above theni ; 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 

 sonsation was experienced and minute purple dots w'cre 

 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 probably injected through a mi- 

 nute 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 fre- 

 quently observed to accompany the sting ; but this may have 

 been either defensive, or simply the consequence of alarm at 

 being rudelj' touched. 



"Some tips of the spines clipped off and placed between 

 slides under a high magnifying power, showed, under varying 

 pressure, a motion of 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 ordy to those of the two subdorsal 

 rows on segments three to ten, and the dorsal spine on seg- 

 ment eleven. These differ from those elsewhere on the body 

 in their fascicular arrangement, their lesser length, the 

 regular taper of the branches, and their tawny color, as ap- 

 pears in detail in the description given of the mature larva. 

 With tills interesting structural peculiarity in mind, the larva 

 may be handled with impunity, as was repeatedly done with 

 the fift}' or more individuals composing the colony from which 

 these notes were drawn, in the frequent transfers, which tliey 



♦That a poison is secreted seems to us improbable.— A. S. P. 



23 



