1919] Blackman — Notes on Forest Insects 95 



lengthwise along the back of the thorax and head as far as the 

 base of the mandibles, and through this opening the head and 

 thorax of the pupa was pushed. It then required only a few min- 

 utes for the pupa to free itself of the old larval skin except where it 

 was continuous with the lining of the alimentary canal at the anus. 

 At this point the larval skin often adheres very firmly and some- 

 times is not dislodged for several days. 



The newly transformed pupa is colorless except for a faint tinge 

 of brown at the points of the dorsal spines of the abdomen. Dur- 

 ing the succeeding seven days various parts of the body acquired 

 pigment in about the following order: — the mandibles, the eyes, 

 bases of maxillae and labrium, joints of femur and tibia, coxse, 

 tarsi, base of antennae, scutellar region. At the end of a week the 

 pupae are ready to transform. The mandibles are motile, the body 

 form is more like that of the adult and the elytra are no longer 

 folded around the body with their tips ventral as at first, but now 

 are dorso-lateral in position. 



The first indication of the moulting of the pupa is a loosening of 

 the pupal skin in the head region. Later the skin here splits and 

 is soon slipped down over the pronotum whereupon the mandibles 

 are used to tear it and release the prothoracic legs. The rest of 

 the process is rapid as the legs are now brought into play and the 

 body soon freed of the loosened covering. In one instance where 

 transformation was observed, the entire process of moulting re- 

 quired eleven minutes. 



The newly emerged adult is by no means as helpless as is the 

 case with many Scolytids, and seems to require a considerably 

 shorter time in attaining its adult color. Adults 36 hours old are 

 brown-ochre in tint with wing covers opaque and in less than a 

 week are dark brown, nearly black in color. There is normally 

 but one generation of Hylurgops pinifex per year in central New 

 York but if the young adults which ordinarily feed in their larval 

 hosts from late summer until the following June are removed from 

 their feeding burrows, they will readily enter a new host and start 

 new brood-burrows. 



As Hylurgops usually occurs only in the lowermost trunk 

 regions, the forms commonly associated with it are of limited 

 numbers. Perhaps the most common is Orihotomicus (Ips) coclatus 

 Eich., which in central New York is nearly invariably found in the 



