4^^ AND ^^^^ 



JOURNAL OF VARIATION. 



Vol. X. No. 8. August 1st, 1898. 



Some notes on the Pupal moult of Lepidoptera. 



By Dr. T. A. CHAPMAN. M.D., F.Z.S., F.E.S. 



lu the Entomol Of list's Ilccord for May last (ante, p. UC), I o-avc 

 some notes on tlie pupal colourinG^ affecting- portions of the larval skin, 

 previous to the moult, in Seolioptcryx libatrix, and referred to por- 

 tions of the pupal skin that tend to assume the brown ehitiuous colour 

 of the mature i)upa before tiie larval skin is cast, instead of the usual 

 green colour. I was able to suggest no reason for this early hardening 

 of ])ortions of the jjupal integument, except in the case of the nuirgins 

 of tlie false spiracle of the thorax, where the tube from the spiracle 

 to the surface, beiug merely between the opposed surfaces of the segments, 

 might easily I'ail t(j l)e formed, if these were entii'cly of the ordinary 

 soft green structure. By having already some hardened chitin for the 

 margins and lips of the tube, the due o])position of the surface is assured. 

 A brief note of the detailed observations bearing on this subject, 

 and relating to certain species, may be useful. 



Sphinx Ugustri. — The larva lies 8 or 10 days in its earthen cell, and 

 gets very sha])by and dirty-looking, from the shrivelling and dai'keniiig of 

 tlie eifete larval skin. Immediately on moulting, the pu])a measured 

 1-87 in. in length, made up of (J) -63 in., from anterior extremity to 

 end of wings. (2) V24< in., to posterior extremity. The segments 

 are all very marked and rounded, with deej) incisions, the teruiiual is 

 full aud blunt, uot tapering as in the i)Ui)a, the 5th and 0th abdomiual 

 beiug especially large and globular. The head stauds out and some- 

 what ai)art, as it does pernuiuently in many Tineid pupiv. The 

 proboscis-case forms a scpiare projection -1 inch iu length and width, 

 but bent down somewhat already, markedly bitid, and the two lateral 

 halves easily se})arated. This case assumed its permanent shape and 

 length of aljout -28 in. in about an hour. Before moult ing, the relative size 

 of the segments had much changed, the ])rothorax beiug large (from 

 head pushed liack into it ?), the first alxlomiual very suiall, etc. The 

 margin of the mesothorax agaiust the 1st spiracle was already 

 l)rownisli. as well as hauges cm 5. (i aud 7 abdomiual scguients. After 

 two hours the relative lengths of measureuients <i\\vw above — (1) = -0.3, 

 (2) = 1-24, had become— (1) = M, (2) = 078. The a])domiiial 

 s])iracleswere widely open, and the winkiug movemeut of a membrauous 

 fold from the posterior wall of the trachea a short distance within, 

 was easily seen. There are in this species no dark ehitiuous parts in 

 connection with these valves. These movements contiuued as lou'^ 



