672 General Notes. [ September, 
common earth-worm comes out of the ground in great numbers, 
and upon the walks through the Smithsonian grounds, for exam- 
ple, where sparrows are abundant, they remain until they are 
dried to a crisp in the sun or crushed by the feet of pedestrians ; 
and the sparrows are meantime rumaging the horse droppings in 
the street for, to them, more acceptable food. If they are really 
an insectivorous bird they surely ought not to refuse earth-worms, 
which are favorite food with such birds.—C. A. White. 
How Insects RESIST CoLD.— The cocoon surrounding an insect 
affords little protection, relatively, to temperature. Where a pupa 
resists congelation, it does so by virtue of a continuous and con- 
siderable liberation of heat. Whence is this production? Ac- 
cording to Dr. Jousset de Bellesme (Les Mondes), it is, very 
probably due to the organic transformations taking place in the 
pupa. Without going so far as to say (with some naturalists), 
that all the organs are destroyed to be built upon another plan, it 
is certain (speaking only of the muscular system) that there is a 
disappearance of certain muscles that have served for the larve, 
and formation of new ones, to be used by the perfect insect. 
Such work could not be done without a reciprocal liberation and 
consumption of heat, which would compensate one another if the 
reconstructed muscles were the equivalent of those destroyed. 
ut the muscular system of the larva is much more considerable 
than that of the perfect insect, hence all the heat rendered dis- 
posable by destruction of the old muscles is not utilized in con- 
struction of the new ones. Further, uric acid and its derivatives 
are found abundant in the insect which has been metamorphosed, 
and this is another proof of the existence of active combustions 
during the pupal period. It is then apparently, to these organ- 
ized chemical phenomena that we must attribute the facility with 
which insects, in the course of transformation, bear very prolonge 
depressions of temperature. 
““Mimicry”’ IN Snakes.—In the NATURALIST for September, the 
question is asked, “ Does the fox-snake ‘mimic’ the rattle- 
snake?” This recalls an experience of mine that occurred sev- 
eral years ago, when collecting plants in the vicinity of Panola, 
Miss. nake of an unknown kind running along in the low 
grass was pursued to some rails that lay in a loose pile on the 
ground where it had fled for safety. By means of a stick of suf- 
ficient length, after finding it, I held it fast to the side of a rail, 
_ when I was surprised and. startled by a buzzing sound from its 
tail. The first thought was that I had a rattlesnake, but a glance 
at the tail and the color of the skin at once disproved this. Feel- 
ing safe from being bitten, the hold was kept, and the phenome- — 
non observed. The tail, vertically flattened either naturally or for 
the occasion, was thrown into rapid vibrations from side to side. 
The snake was very angry at being held, and I thought this its 
