66 



F. A. DiXEY, in reply to the discussion, agreed with Dr. Long- 

 staff that both the volume and duration of the odour diñered 

 much from species to species. There was no doubt that the 

 anatomical relations were different in different cases. He had 

 pointed out that the special distribution of tracheae described 

 by him was only to be found in relation with certain circumscribed 

 scent patches, and not in connection with the generally dispersed 

 scent scales. He fully agreed with Dr. de Meijere that the 

 glandular structures in insects and other Arthropoda had usually 

 a peculiarly rich supply of tracheal branches, but he could not 

 help thinking that there was some more special significance in the 

 distribution to the scent patches. He had elsewhere attempted 

 to connect this with the difíerences in structure which charac- 

 terised respectively the two kinds of scent scale. 



G. H. Carpenter then gave his paper entitled : 



The Presence of Maxillul.e in Beetle Larv.e. 



Importance of the maxillulas as corresponding with the first 

 maxillae of Crustacea. Larva of Dascillus cervinus chosen for 

 examination. Maxillulae found in this larva, and also in that of 

 Helodcs. In Phyllopertha the structure is asymmetrical. Ac- 

 count of a Helodine larva found at leaf bases of Bromeliaceous 

 plants in W. Indies. Maxillulae recorded by Mangan in larvae 

 of Dytiscidœ. Presence in Pterostichus of structures correspond- 

 ing to the maxilluke in Dytiscidœ. 



The paper was illustrated by lantern slides (cf. Vol. 11., p. 208). 



R. S. Bagnall said that he had examined the mouth parts 

 (and the maxillulae) in many species of Symphyla, Isopod Crus- 

 tacea, Thysanura, and Crustacea, and also the foot of the Thy- 

 sanura, Collemhola, and the larvae of various beetles, and he 

 considered that the Thysanura foot had affinities on the one side 

 with the Symphyla, and on the other with the larvae of certain 

 beetles, mentioning certain Scydmœnidce and Dermesters. He 

 mentioned Tomosvary's description of a supposed new type of 

 Thysanuran, Anisosphœrius, which was later discovered by 

 Silvestri, and raised as the type of a new group of Thysanura 



