( Ixi 
Dr. Chapman also exhibited on behalf of Rev, C. R. N. 
Burrows a specimen of malformation of the male appendages 
in Acronycta tridens. No similar specimen appears to have 
been recorded. Instead of occupying their proper situation, 
the clasps, penis, and penis-sheath formed a mass in the 
interior of the abdomen, and were accompanied by two, 
apparently chitinous, bodies, that could hardly be anything 
else than the two tubercles that represent these parts in the 
pupa. The specimen suggests in the strongest way that the 
parts placed internally are really internal parts, that become 
external at pupation, and have in this specimen remained 
internal through an arrest in the development of the indi- 
Diagr itn to show the parts in noriral relations to each other and to the pupal skin 
A pupal skin ; B parts external in specimen ; C parts internal in specimen. 
vidual. It may bear on this that the spines on the eversible 
membrane {vesica, Pierce) are poorly developed, though the 
rest of the parts are fully foi’med, but owing to their situation 
poorly displayed. On the other hand, all the authorities 
agree that the clasps at least are dermal appendages, and 
are developed from dermal structures of the 9th abdominal 
segments, though any clear demonstration of this appears to 
be lacking; but in support of this view (the dermal origin of 
the clasps) they possess scales and hairs which can hardly be 
possessed by processes from the interior. Another hypothesis 
would be that the clasps are dermal, but become internal for 
a time (not unlike the wings) and here failed to return. The 
specimen in fact raises more questions than it settles. 
