222 PROCEEDINGS OF SCIENTIFIC SOCIETIES. 













through the head and out at the back of the insect. As the head always — 
points towards the base of the leaf, Mr. Sanborn believes that when the — 
insects wish to rid themselves of their exuviæ, they perch themselves 
upon a blade of grass or needle of pine, sar thrusting their heads against 
a contiguous leaf, force the skin backward. He exhibited skins of the i 
plant lice, which, although very ee had been emptied of their com 
tents by internal parasites fter the transfornaiia of the parasite it 
had gnawed a nearly iinit circle through the dry skin, thus partially 
detache a nearly rounded lid or cover through which it could make its 
scape. a 
Two of the most curious specimens exhibited were acorn cups which 
had been used by spiders; in one, the opening had been flatly roofed ovet 
with a web, leaving only a small aperture for ingress and egress; in the : 
other, the cup was closed by a finer web with no opening whatever; when 
examined, neither spider, young, nor eggs were discovered within; this 
was probably an instance of a curious instinct which leads pegs eer a 
o expend much time and labor in preparing for an me í 
Dec. 4.— The Secretary read a a paper by Mr. A. S. Bickmore, we, gii A 
of the treatment of the dead among this people, as similar practices pi 
vailed among the North American Indians; this, he thought, pointed to / 
common descent. To strengthen his argument, he endea avored to show 
that the Ginseng, or panacea of the Chinese, was obta ined from & 
which only grew in the valley of the Ohio; in this case, close ¢ per 
tion by the way of the Aleutian Isles must have taken place between 
two nations. 
r. Perry aia a paper upon the red sandstone of — i 
and its relation to other rocks. Mr. imed that the red 
sto he equivalent a the Potsdam sandstone of the New A 
geologists, and that the adjacent formations to is antes Abe cot | 
highly metamorphosed rocks of a more recent p as h ie : 
and Jay wacom 
yee beneath it. she Silt 
or Agassiz stated that he had recently been vier ee 
roid pach for the sake of illustrating the definitions he had long © 
presented for the different categories of structure among 
Siluroids had always been considered a natural group; placed, : 
a single genus which was subsequently divided into two, they pao ] 
considered a family including several genera, and finally an osii jn the 
ing several groups termed families. Was there then no m “that th : 
erms genus, family, order? Professor Agassiz urged $ strongly esi 
application of these terms should be uniform, since a genus ee 
a genus no matter how numerous its subdivisions. H 
orders were founded upon degrees of complication of structure, 
lies upon the forms of animals. 
