BSI CHE . BAI 
length, separating at the posterior fourth 
to admit the passage of muscles which 
are described later. 
missures are slightly enlarged posterior 
to the first thoracic ganglion (c). 
The united com- 
The muscles which cross each other 
between the commissures connecting the 
first and second and second and third 
thoracic ganglia are generally found in 
lepidopterous larvae, and serve to hold 
the second and third thoracie ganglia in 
the median line. The mode in which 
these muscles cross each other and inter- 
lace the commissures, as seen in the fig- 
ure, is the same between the second and 
third as between the first and second 
thoracic ganglia. This mode of inter- 
Jacing of the muscles and commissures 
is exactly the same in the larva of Sphinx 
ocellata as it is in that of Harpyia. 
The kind of asymmetry existing in 
the nervous system of the larva of Har- 
oe 1 RON 
pyia has been found, as far as I know, 
in no other arthropod, but, upon sugges- 
tion of Professor Leuckart, of Leipzig, 
in whose laboratory I was studying when 
I discovered the asymmetry in the ner- 
vous system of the larva of Harpyia, I 
Hirudo the 
blood-leech, the nervous system of which 
examined medicinalis, 
has an analogous asymmetry. The gen- 
ital organs are in such a position, in 
Hirudo, as to necessitate the pushing 
of the nervous system slightly to one 
side, near their outlet. 
Of four specimens of Hirudo exam- 
ined, two had the nervous system to the 
right and two to the left of the genital 
organs ; but of six specimens of Harpyia 
dissected, all had the commissure be- 
tween the first and second thoracic gan- 
elia deflected toward the left. 
Parts, France, 3 Dec. 1881. 
CATOGENUS RUFUS. 
BY GEORGE DIMMOCK, CAMBRIDGE, MASS. 
Ix the winter of 1878-1879 I received, 
from Suffield, Conn., a lot of nearly 
full-grown larvae of Elaphidion parallel- 
wm in twigs of Carya alba. 
these larvae, in a portion of a twig split 
in two parts which were carefully and 
tightly held together by a rubber band, 
was reserved upon my writing-table for 
the purpose of taking notes on its trans- 
formations. This larva pupated in the 
early part of March, and was then in 
an apparently healthy corglition. 
A short time after the larva of Ela- 
phidion had pupated, a small white larva 
One of 
made its appearance in the cavity of the 
wood, in which the pupa was confined. 
As the pupa seemed in no way injured 
I could not determine whether or not the 
larva had hatched from an egg within the 
pupa. was shown at the 
o8th meeting of the Cambridge entomo- 
logical club. It was then very small and 
had the appearance of being lepidopte- 
rous. Supposing it to be €he larva of 
some kind of museum pest that had, in 
a mysterious way, gained access to the 
pupa, I took no description or figure of 
it. It grew slowly, devouring the pupa 
This larva 
