BY R J. TILLY A RD. 



809 



and is evidently formed more as a pad or receptacle, against 

 which the I'ight mandible can work. 



The maxilhe and labinni lesemble those of tlie imago fairly 

 closely, hut are broader and softer, as if the parts were all 

 swathed in whitish bandages. The principal differences are that 

 the galea of the maxilla is a broad rounded lobe without a small 

 distal joint, and the median lobe of the labium is simply bifid, 

 instead of being formed as in the imago. 



After about a week, the imaginal colon is loegin to appear upon 

 the body and wings of the pupa. Before emergence, the whole 

 beautiful pattern of the wing-colouration becomes set fortli upon 

 the wings of the pupa. It was by this means that I was able to 

 recognise the pupa of Ps. ccelivagus, with its intensely black wings, 

 in spite of the fact that it failed to complete its emergence, 

 after escaping from its cocoon. 



Emergence of the Imago. (Text-fig. 11). 



The pupa emerges from the cocoon by cutting it neatly open 

 with its sharp mandibles, whose scissor-like action is specially 

 adapted to this purpose. Alwut one-fourth of the circumference 

 is left uncut, forming a strong hinge. The pupa pushes up the 

 lid of the cocoon, and climbs out. 



On Dec. 1st, 1915, at 5.30 p.m., I noticed a pupa emerging 

 from its cocoon, which was placed upon some sand in a glass-jar. 

 The pupa crawled along the sand to a strip of blotting-paper, 

 placed nearly vertically, near by. Up this it climbed to a height 

 of about one and a half inches, and then took a firm grip of the 

 blotting-paper with its claws, and remained resting for a few 

 minutes. During this time, it gradually swelled up and became 

 very taut, as shown in Text-fig. 11, a. At 5.37 p.m., it began to 

 work its abdomen and wing-sheaths about; so that, in a few 

 seconds, the fine pupal skin split dorsally down the thorax, tlie 

 abdomen became straightened out, and the imago began to 

 emerge from the pupal skin. During emergence, the wings begin 

 to expand at once, the insect arching tliem strongly outwards, as 

 may be seen in Text fig. 1 ], c,d. The basal portions of the wings 

 begin to enlarge before the apical portions are freed from the 



