148 THE CANADIAN ENTOMOLOGIST. 



around each spiracle, probably the vestige of a stigmatal stripe, as a 

 similar spot, in line vvi'.h the others, is to be found on the thoracic segments 

 without spiracles. Spiracles yellowish-brown or buff; dorsal shield 

 (thoracic) white or yellowish anteriorly, near the incisure livid or with a 

 rosy tinge (possibly by contrast with the green), and studded with dark 

 brown, slight elevations. Head above gray-green or brownish-yellow, 

 labrum and mandibles rich brown, ocellar fields black. Pile red (?) 

 brown — possibly also by contrast. 



The body markings are evanescent, and are conspicuous for a day or 

 two only, when the larva has attained its full growth, or a little before; they 

 fade rapidly as the time for pupation approaches. The mediodorsal line 

 grows fainter, and as it does so the indications of the stigmatal line 

 appear. Then all the markings gradually fade, the line on the substig- 

 matal fold being the last to disappear. While this is taking place the 

 caterpillar eats little or nothing at all, the body grows shorter, the 

 segments fill out, obliterating the laterodorsal ridges and reducing the 

 folds and fove?e considerably. In one case the posterior half of the 

 abdominal dorsum became tinged with dull russet-yellow, but as the 

 chrysalis which was formed never disclosed an imago, this coloration was 

 probably due to pathological conditions.. 



The Change to Chrysalis. — Having found the emergence of the pupa 

 instructive in tracing the life-history of other species, I took precautions to 

 witness it in the case of augtistus. Slight peristaltic movement was 

 noticed shortly after midnight (June loth, 1906) in one of the larvce 

 fastened to its final mat. This was repeated at intervals for more than 

 three hours, the peristalsis becoming more violent and the periods of rest 

 less frequent, until at 3.23 a.m. the old skin split along the dorsimeson of 

 the thorax. Three minutes later the exuviae had been pushed beyond the 

 body, the cremastral booklets were fastened, and the insect was quiet. 



The Chrysalis. — The newly-formed chrysalis was bright green on the 

 head, thorax and wing-covers, gray-green on the abdomen ventrally, 

 yellowish-white dorsally ; the pulsating dorsal blood vessel (plainly visible 

 on mesothorax, and second to seventh abdominal segments) dark green ; 

 incisures brownish-yellow ; spiracles nearly white. Six series of shallow 

 pits on the abdomen represent the principal fovese of the larval skin ; the 

 lateral series largest, rounded ; the infralateral smaller, elongate ; the 

 others minute. (See Plate 3.) The position of each pit is usually 

 marked by a spot of black pigment beneath. 



