MICROI'TERYGIDAE 437 



the larval period of feeding and the imaginal instar, the pheno- 

 mena of life are essentially like those of Trichoptera. The larva 

 has not been at all satisfactorily studied ; the spiracles appear 

 to be excessively minute, but have been ascertained by Dr. 

 Chapman to be normal in number and position. 



All the information we possess points to profound distinctions 

 between Micropteryx and Eriocephala, for whereas in the former 

 the mandibles drop off from the pupa, so that the imago has no 

 mandibles, in the latter the mandibles exist, as they do in 

 several other true Lepidoptera. As the history of the mandi- 

 bles is not known in other Lepidoptera (where they are present 

 in the larva but wanting in the imago), it is premature to 

 conclude that no other Lepidoptera suffer the actual loss of the 

 mandibles as Micropteryx does, though there is nothing to lead 

 us to believe that in any other Lepidopterous pupa are the 

 mandibles specially developed as they are in Micropteryx. This 

 pupa is in fact quite unique in this Order of Insects. When the 

 history of the pupal mandibles is known, we shall be able to 

 decide whether they are secondary structures, like the deciduous, 

 supplementary mandibles found in Otiorhynchides (Coleoptera, 

 Ehynchophora). 



