BY R. J. TILLTARD. 807 



libera, closely reseiiibliug the imago in everything except its 

 uuexpanded wings (Plate Ixxix., fig. 7). At the metamorphosis, 

 the pupa experiences a great difficulty in casting oflP the hard 

 larval head, and a number perish from inability to do so. The 

 rest of the larval skin is soft, and shrivels up into a minute mass 

 within the cocoon; the head may be found sometimes almost 

 intact, sometimes with the mandibles and maxilhv broken off 

 from it. The splitting of the head is mid-dorsal ly and postero- 

 transversely, as in the other larval ecdyses (Text-fig. 3). 



The change from larva to pupa does not take place until a 

 considerable time after the spinning of the cocoon, generally 

 from a fortnight to three weeks. At first, the fresh pupa is 

 almost colourless, the body having a slight greenish tinge, the 

 head and wings cream-coloured. The compound eyes are large, 

 and soon become dark brown and functional. If the cocoon be 

 opened, the pupa watches every movement with anxiety, and 

 can be made to turn round and round, merely by the movement 

 of a pin held at a short distance in front of the head. 



The antennce, are fairly short (Plate Ixxix., fig. 7), but are com- 

 posed of a large number of joints, there being thirty-five in the 

 pupa which I dissected. Each joint is less than half as long as 

 wide, except only the first three; of these, the basal joint is 

 stouter than the rest. Unlike those of the imago, the antennte 

 in the pupa are devoid of hairs. 



The mouth-parts are of considerable interest (Text-fig. 10;. The 

 lahruin is distinctly bifid, and carries numerous hairs on small 

 raised bases. Below the labrum, on either side, are the large 

 and very strongly chitinised mandibles. Each of these consists 

 definitely of two lobes, separated by a narrow slit. The outer 

 or distal lobe has a sharply pointed, tooth-like apex, and, below 

 it, a more or less broad and fiat cutting-area, forming a right- 

 angled projection. The inner or basal lobe is rounded, and much 

 less prominent. The two mandibles are not similar in shape. 

 The right mandible has the smaller basal lobe, but the broader 

 and flatter cutting-surface; wliereas the left mandible has the 

 cutting-area narrower, and the apical tooth raised above it on a 

 high ridge. Thus, in the action of cutting open the cocoon, for 



