30 BRITISH LEPIDOPTERA. 



is observable over the prothorax, and a pink spot appears on the meso- 

 thorax, just behind the first spiracle. During, and just after, the 

 moult, the colouring of the prothorax is seen to affect precisely that 

 part of it that is exposed in the pupa, whilst a slight tinting exists 

 over both the meso- and metathorax. The pink spot is seen to be the 

 posterior lip of the thoracic spiracle, as usually seen and described in 

 the pupa. In the pupa of Phalera bucephala, the portions coloured at 

 the moult are only the anal spines, and the adjacent margins of the 

 last two abdominal segments, where they are sculptured. In Sphinx 

 lif/ustri, the mesothoracic margin, at first spiracle, is already coloured 

 brownish at the moult, as well also as the flanges along the sides of 

 the 5th, 6th, and 7th abdominal segments. It seems to be very usual 

 for the posterior margins of the first spiracle to be already slightly 

 matured. In 8. ocellatw, the lips of the prothoracic spiracle, the 

 posterior margin of the 7th abdominal segment, the pale bands on the 

 dorsum of the metathorax, and the 2nd and 3rd abdominal segments, 

 as well as many of the small cutaneous pits, become brownish at the 

 time the larval skin is moulted. I think, in these, and in other, 

 instances, two points appear, the first is that no portion of the pupa 

 can be allowed to harden and colour before the moult, that has to 

 undergo any expansion or contraction during the alteration in form 

 that occurs just after the moult. The second is the special case of the 

 thoracic spiracle. What we call the thoracic spiracle in the pupa, is 

 not the spiracle itself, which has the same structure, or nearly so, as 

 the other spiracles, and is buried deeply in the fold between the pro- 

 and meso thorax, and communicates with the surface by a narrow slit, 

 but is the opening on the surface and is between the two segments 

 close to the antenna. The margin of one or of both segments, here, 

 is very often, indeed usually, specially wrinkled, striated, or otherwise 

 characteristically and beautifully elaborated. It is very important, 

 therefore, that these margins should, on the moult to pupa, fall exactly 

 into their right places, and as this would often be apt to fail, if they 

 were as soft as the rest of the pupa, we can understand why they are 

 so usually (? always) coloured and hardened to some degree before the 

 moult takes place." By having already some hardened chitin for the 

 margin and lips of the tube, the due opposition of the surfaces is 

 assured. As bearing on Chapman's view as to the parts which thus 

 appear to become prematurely coloured (hard and chitinous), being 

 already matured and potentially functional, we may note an observation 

 made by Edwards as to the rapid formation and hardening of the knobs 

 to which the " Osborne membrane " is adherent, in certain Nymphalid 

 pupas in process of formation, at the critical point of fastening the cre- 

 mastral hooks into the silken pad. This reads : " It is useless, I think, 

 to search for this membrane until the latter end of the suspending 

 period of Anoria archipjms. One thing is certain, it is not till late in 

 that stage that these knobs do show themselves, but they are then soft 

 and white, becoming hard (chitinous) just when they are needed." 



Owing to the exceedingly different habits and surroundings of the 

 quiescent pupa compared with those of the mandibulate larva, great 

 changes occur when the pupal state is assumed. In many lepidopterous 

 pupae the mandibles are entirely wanting, whilst the 1st maxillas are 

 highly developed and specialised, the head is entirely modified in shape, 

 the antenna? and legs, rudimentary in the larva, are well developed, 



