a T. “whe 
; a dubai Sa a oe 
+ ae Fs . 
148 Motion of Particles on Melted spalieenonts * rie 
i 
* 
the former, after anumber of days, (six or eight, ) was'as much a 
flirt as ever, wriggling and flouncing at every touch. ~ My 
December 12, 1840.—In a former letter, I contrasted the vi- 
tal tenacity of a Lepidium, with that of a common fly. The 
Lepidium is still alive. It has been kept-since the date of that 
letter as it had been before, in a perfectly- clean cupping glass, 
covered with another cupping glass,-so that to human perception, . 
life has been sustained without subsistence for many months. 
The continuance of the insect’s existence is in no degree due toa 
‘state of torpidity during this cold weather. be 
In the summer, the larve of the lady-bug, (slate-colored wings 
with sixteen black dots, the two near the neck approximate, ) were 
very numerous about my residence, and attached themselves, af- 
ter their aphidivorous career, to the trees, walls and other neigh- 
boring objects, by their posterior extremity. The little birds stole 
away many of them; but others were well ensconced, and they 
fellto my share. Thus adherent, the larve struggle by occasion- 
al jerks, for several days, to disengage themselves from their et 
velope. At last a buff-colored, elliptical and rugose thing appears, 
the old integument having been slipped down into a dense mass; 
and in twelve hours, the black spots appear upon its partially de- 
veloped wings. It remains firmly fastened to its original point for 
a day or two longer, when another integument is thrown off as 
before, and the perfect bug walks forth. It does not immediately 
leave the spot ; but remains a long time in the vicinity of its exu- 
vie, perambulating around them as if exulting at its escape from 
so mean a habitation. These larve are covered with spines. In 
several instances, those that were so unfortunate as to have attach- 
ed themselves early, were attacked by those still at liberty, and 
destroyed : the prisoner showed by his contortions, &c., that he 
suffered from the wound. 1 saw one of the semi-developed bugs 
destroyed in the same manner; and one of: the perfect bugs prey 
ing upon an attached larva. Thus voracity continues through 
all the stages of its metamorphosis: the larva living upon its own 
grade, and the winged bug, upon the larve. 
Motion of Particles on Melted Spermaceti.—In relation to som? 
remarks in a former number of this Journal, Vol. xxxut, p- 198, 
a singular phenomenon in a burning candle, in which a particle 
floating upon the melted spermaceti, alternately approached to 
