ON THE NORTH AMERICAN COSSID. 3 
caterpillars. Again three crops of larve were found; the larger ones 
were inactive and lying in the sap-wood, with their heads close to the 
bark which was ‘gnawed nearly through to the outer surface. These 
caterpillars had evidently taken their last position preparatory to their 
final transformation into pup. Pup were also found occupying the 
same position, and when the bark was removed were visible. 
The larvataken October 14 from its burrows is 45™™ in length, of a pale 
flesh color. It is a little broader anteriorly. The prothoracic segment 
is blackish brown above, the dark color edged with a dirty orange shad- 
ing. The head is mahogany brown, shining, slightly roughened. The 
mandibles are black, with strong teeth. The surface of the head gives 
rise here and there to single scattered hairs. The antennz are three- 
jointed; the second joint gives rise to a single long hair. The seventh 
eighth, ninth, and tenth abdominal segments are provided with false 
feet. The segments are marked with a lateral row of brown dots above 
the reddish stigmata, and there is a row of similar dots, two to a segment, 
on each side of the dorsal line. These dots give rise to single pale hairs. 
The larva moves with freedom either backward or forward. The bur. 
rows which it excavates are about 15™" in width and terminate in the 
pupating cell, which is about 40™™ in length, smooth; the extremity 
towards the opening is closed by a wad of finer and then coarser filings 
of the wood. The coarser splinters are not detached entirely from the 
wood, but are split up by the larve all around the top of the cell, and 
project like bristles, appearing somewhatas those wooden toy trees which 
are made for children, and which are formed by shaving down the wood 
and leaving the shavings adhering by one end. These splinters make 
a firm wad. Against them are piled a quantity of finer chips or thin 
filings, which are loose but pressed together. 
The cell (Plate 1, Fig. 7) isabout 40™™ from the outer bark of the tree, 
and the chrysalis (Figs. 8 and 9) makes its way to the air through the 
burrow, by means of its teeth on the segments and the spinose process 
on the front, by which it forces itself, by stretching and contracting the 
abdomen, through the wood scrapings which close the cell, until it comes 
to the end. We have noticed a fine thread of silk proceeding from the 
spinneret of the‘larva, although in the cocoon we have found no silk 
whatever. The cocoon or pupa-cell seems to have been formed by wedg- 
ing first coarser and then finer strips of the wood together, and seems 
to be merely a more carefully and smoothly finished aes of the 
original burrow. 
A specimen of the pupa which I have examined is about 50™™ in length, 
narrow, brownish black, shining rugose. The clypeus presents a strong, 
broad, spinous process, supported at base by lateral projections. On 
the under side it descends into a wide sulcation terminating in a broad 
projection. The capital appendages are visible, and here and there arise 
isolated hairs as in the previous stage. The abdominal segments are 
provided with teeth over the dorsum, decreasing in size to the stigmatal 
