ON' THE NORTH AMERICAN C08RID.fi. 51 



caterpillars. Agaiu three crops of larvae were found: the larg< 

 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 pupae. Pupa- were also found occnpying the 

 same position, and when the bark was removed were visible. 



The larva taken ( October 14 from its burrows is 45 m ™ 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. Tin* 

 mandibles are black, with strong teeth. The surface of the head gives 

 rise here and there to single scattered hairs. The antennae 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 pah- hairs. 

 The larva moves with freedom either backward or forward. The bur 

 rows which it excavates are about 15 m,n in width and terminate in the 

 pupating cell, which is about 40 ,nm 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 larva- all around the top of the cell, and 

 project like bristles, appearing somewhat as 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) is about 40 ,nm from the outer bark of th^ i 

 and the chrysalis (Figs. S 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 coiner 

 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 v 

 ing first coarser and then finer strips of the wood together, and seems 

 to be merely a more carefully and smoothly finished enlargement of the 

 original burrow. 



A specimen of the pupa which I have examined is about :U)" !n in length, 

 narrow, brownish black, shining rugose. The clypeus presents a strong. 

 broad, spinous proa ss, supported at base by lateral projections. On 

 the under side it descends into a wide Bulcation 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 t<> the stigmata] 



