220 THE entomologist's kecord. 



of the skin being cast, I noticed what could not be bettor described 

 than by saying that these spiracles winked at me. The brown- 

 coloured portion was now at the bottom of an oval slit, not much 

 wider at the surface than below, but just within the outer opening 

 there descended from above, and hid the brown base, a pale green 

 diaphragm, exactly like an eyelid, and then rose again. I examined 

 this process through a strong pocket lens, and when I took to timing 

 it, found it occurred once every three seconds, the opening being now 

 the shortest part of the sequence, and lasting half a second. I could 

 not be sure that they were simultaneous with the vermicular move- 

 ments, but they continued till the spiracular openings became too 

 narrow to see them distinctly. It may be an entirely erroneous con- 

 clusion, but I could not resist the idea that these were valvular 

 arrangements, associated with the pumping process necessary to the 

 expansion of the appendages. They may be merely a development 

 occurring (rapidly like that of wings) for the occlusion, more or 

 less complete, of the spiracles during the pupal state ; but then, are 

 the spiracles quite occluded during the pupal state ? I doubt it ; and 

 secondly, why the winking ? A gradual development would be all that 

 was necessary, as with the wings, which do not flap as they increase in 

 size. This is obviously a matter that wants following up. I ought, 

 perhaps, in order to be more clear, to say that the observation was, of 

 course, made as the pupa hung in its natural inverted .position ; the 

 descent of the eyelid was therefore from the posterior margin of the 

 spiracle, the final narrow slit being parallel Avith the lines of incision, 

 or nearly so. I was unable to make any observation on the spiracle 

 of the first thoracic segment. 



When the pupa has assumed its permanent squat rounded form, 

 it is still very soft and delicate, and for several days, if touched or 

 disturbed, it is capable of movement, which afi'ects the incisions on 

 either side of the 5th and 6th abdominal segments, and seems also to 

 produce flexion of the pupal integument ; but later, say a week after 

 moulting, the pupa appears to be solid and incapable of movement, 

 but considerable irritation produces a trifling amount of movement, 

 not of flexion, but of retraction, so that these segments (5th and 6th 

 abdominal) are in this species both free. For some hours before 

 emergence they are fully extended, as they never are during pupal 

 quiescence, by the inflation that is so general a phenomenon in insects 

 at emergence from the pupa. 



My pupa?, brought to England, continued in the pupal state about 

 five weeks, and of this period, the time necessary to the development 

 of the imaginal colours, appeared to me exceedingly short. After some 

 increase in opacity of the ordinary green tint, the brown colour of the 

 margin of the fore-wings became evident and fully developed as to 

 colour, whilst the rest of the wing was still green, then the black 

 colour of the mass of the wing appeared. From the first trace of 

 brown colour to emergence, only 38 to 48 hours elapsed, and from its 

 full development, before any black appeared, to emergence, less than 

 80 hours ; in one case, on a warm day, less (I do not know quite how 

 much less) than 21 hours. A high temperature would doubtless 

 diminish even these periods. 



