OF WASHINGTON. 91 
April 13, 1904, a Cerambycid pupa of an unknown species 
(allied to Goes, and possibly Goes oculata) was found in a 
small chestnut which had died the previous summer. 
On April 16 this was carefully examined and described, 
and on the following day, another careful examination dis- 
covered a very minute larva attached to the ventral surface 
of the abdomen, which was at first supposed to be that of a 
Hymenopterous parasite, but subsequently found to be Coleop- 
terous. This larva, which was extremely minute and hardly 
visible without the aid of a lens, was believed to have hatched 
during the day intervening between the two examinations. 
It was attached by its head only (a faint dark colored spot 
soon appearing upon the body of the host at that point), and 
its body projected at an angle from that of its host. 
For several days it remained in this position, increasing 
slowly in size, until the i9th, when it was found to have relaxed 
its hold, and was removed to a freshly pupated Callidium 
aereum, in the hope that the wound already inflicted on its 
host might not necessarily be fatal. Careful examination 
showed that this pupa was slightly wounded on one of its 
tarsi shortly after the introduction of the parasite, but the 
latter could not be observed to feed until May 8, when it was 
found to have moulted. The new host at this date was still 
alive, as was also the pupa upon which the parasite was origi- 
nally found. 
May 10 it was feeding freely and growing rapidly, and 
the new host appeared to be dead. 
May 20 it had completely destroyed its host, and no 
trace of cast skin to indicate that it had moulted again could 
be found. It was then resting quiescent, and remained so 
until June 3, when it pupated. The pupa was entirely un- 
changed June 1 6, but July 3 was found to have produced a 
perfect Catogenus rufus. 
On April 13, and on the same tree as that from which the 
above mentioned specimen was taken, a cocoon of one of 
the well-known parasites of the Cerambycidae, Bracon dorsatus, 
Say, was collected and placed under observation. July 5, on 
examination, a second specimen of Catogenus rufus was dis- 
covered, plainly visible through the parchment-like walls, 
and careful examination failed to discover any visible aperture 
by which any larva might have entered. This specimen was 
considerably below average size, while that bred from the 
Cerambycid pupa was, though much smaller than some speci- 
mens, about an average between the largest and the smallest. 
A third specimen was afterward reared under still more 
interesting circumstances, and serves to confirm its life-history 
as above set forth. 
