OF WASHINGTON, VOLUME XVI, 1914 157 



The maxillary palpi (fig. 17), are bent upon themselves in five 

 sharp curves, with the last joint pointed downwards and forwards. 



The two halves of the proboscis are widely separated and out- 

 wardly curved, with their tips nearly meeting in the middle line 

 forming a heart-shaped figure. 



The labium and its three-jointed palpi are pointed downwards 

 in two straight, divergent staffs, reaching beyond the curved pro- 

 boscis. 



The strongly angulated patagia, 1 (fig. 19), overlap the base of 

 the wings behind. 



The legs are folded loosely along the body, the posterior tarsi 

 reaching beyond, and curved around the tip of the abdomen. 



On the back of the pupa is a peculiar structure, the morphology 

 and function of which is not clear to us. It consists of an un- 

 paired, thin-walled, strap-like, longitudinal band (fig. 21, x), made 

 up of three separate appendages in prolongation of each other and 

 attached to the middle line of respectively the second and third 

 thoracic and the first abdominal segments. 



Each abdominal segment bears two lateral pairs of strong stiff 

 spines. The spiracles are small and circular. 



In early spring when the pupa is mature and ready for the 

 emergence of the adult, the cocoon is split open by an outward 

 movement of the mandibles which tears through the tough silk. 

 The pupa then wriggles out of the cocoon and laboriously digs up- 

 ward through the earth by the help of the mandibles, swung from 

 the exceedingly movable head and pushed on by the movements 

 of the abdomen. When it finally has made its way to the sur- 

 face, it lies immovable for some time, during which the last acts 

 of the transformation to adult take place. The mandibles be- 

 come immovable through the withdrawal of the imaginal skin and 

 mandibles, together with the strong muscles which remain in the 

 imaginal head. The pupal skin now splits open on the median 

 line of the first and second thoracic segments. The long-haired 

 head and thorax of the imago appear in the slit and the fully 

 developed moth issues. It at once seeks some support from which 

 to hang with backwardly extended wing, as is usual with freshly 

 emerged moths, but it is very quickly in condition for active 

 flight. It is interesting to note that if the cocoon is taken out of 

 the sand and placed on the surface for observation, as was done 



research for some microanatomist. I fear my own training leaves me un- 

 equal to carry the matter much further. I am however, thoroughly satis- 

 fied on two points: first, that there are no muscles attached to these jaws, 

 second, that there are no imaginal jaws within them, whose movements 

 compel those of the pupal ones." Chapman, Trans. Knl. Soc. Lond. 1893, 

 pp. 255-263. 



1 The patagina of Busck, by mistake. 



