13 Proceedings of the 



yellowish green, and adorned with purple black markings ; the fact being 

 that he takes his description from the newly changed chrysalis of the one, 

 but not of the other. The paler cream-coloured covers of the wings are very 

 conspicuous in each of these, though more opaque in Tithonus. In 

 Janira there is little other after-change of colour except a gradual fading out 

 of the green in the abdomen, and consequent increase of the cieam-coloured 

 hue over the entire pupa-case until the morning of the third day before 

 emergence, when an oval dark blotch, placed endways, appears on the centro 

 of the inner margin, continually intensifying in depth of colour ; this doea- 

 not, however, seem to expand, but is ultimately absorbed in a cloud that 

 comes over the middle of the wing-case. The change is gradual, and a very 

 slow process, taking the whole of one day to complete, when the ocellus of 

 the wing is distinctly visible ; a small dot placed in the centre of the pupal 

 wing-case, apparently for ornament, becomes at this time surrounded with 

 a narrow red ring ; the cream colour of the chrysalis, too, has deepened inta 

 a reddish buff. The nest day the colour increases so much that the ocelli 

 are no longer visible ; towards evening a bluish bloom appears, the asperitie« 

 of the cases show the minute white dots mentioned above, and finally the 

 perfect insect escapes between 8.30 and 10.0 of the following morning, and 

 is ready for flight the same afternoon. The fact of the pupa being suspended 

 head downwards does not seem to interfere with the actual emergence at 

 all, this being very rapid ; when completed, the imago immediately turns 

 round, and climbing up the pupa-shell, ascends to a favourable place for 

 development. I wish particularly to draw attention to the oral dark mark 

 on the inner margin of the wing-cases in this species ; it is something very 

 unusual, indeed, quite new to me, for I know no other insect where in pro- 

 gress of change for emergence a distinct mark appears on the pupa, not 

 afterwards perceptible in any form in the imago. No such dark mark is 

 seen when Tithonus approaches the period of perfection ; the gradation of 

 changes here affords nothing striking to record, excepting the lovely rose- 

 colour of the pupa at one time, and increased number of markings on its 

 external coat, such as may be often noticed on Brassicie and Cratsegi. Its 

 final internal changes would also seem to be more rapid, as it is ready for 

 flight within two hours from time of emergence. The motive power which 

 enables the newly-born imago to force its way from the pupa shell has been 

 suggested as something akin to hydi-aulic pressure. I do not think this expla- 

 nation satisfactory, for the exudation from the body into the posterior seg- 

 ments of the chrysalis shell is in itself but small, as we may see upon after 

 examination ; its real use appears to me a lubricant, for when forced by 

 pressure upwards it prevents adhesion between the as yet imperfect scales 

 and the shell. If deficient in quantity a torn or more or less scaleless wing, 

 is the result, sometimes a total cripple. Passing to the Sphingidje, the 

 phenomena connected with the extrusion of the perfect insect are too well 

 known to dweU on in externa. In escaping, the portion of the chrysalis 

 enclosing the head, antenna, and legs is detached entire. I will only 

 remark that Ligustri should be added to Dr. Swinton's list of stridulating 



