258 Mr. G. F. Hampson on the 



structure except in the possession of a fully developed frenu- 

 lum and retinaculum. 



Dr. Chapman's contributions to the classification of the 

 Lepidoptera are entirely derived from a study of the early 

 stages, more especially the segments of the pupte. He shows 

 that in most of the families of what are usually termed Macro- 

 Lepidoptera, and also in the Pyralida*, and some of the higher 

 subfamilies of the Tineidse, the movable segments of the 

 pupa^ are the fifth and sixth abdominal in both sexes, that 

 they have no power to emerge (as pupte) from the cocoon, 

 and that dehiscence on the emergence of the imago is by 

 irregular fracture. On the other hand, in all the lower families 

 of the Micro-Lepidoptera the pupa is much less solid, the 

 appendages often partially free, the free segments may extend 

 to the third abdominal, and the seventh segment is always 

 free in the male, fixed in the female. Also that dehiscence 

 is accompanied by freeing of the Segments and appendages 

 previously fixed, and that the pupa has the power of pro- 

 gression and emerges from the cocoon, except in the Ptero- 

 phorida?. And he proves that the Sesiidse, Psychidas, Cossidaj, 

 Hepialidge, Zyganidse, and Limacodidse belong to this lower 

 group of families, in which he is entirely supported by the 

 structure of the imago. 



The following key is intended to summarize our present 

 knowledge of the relationships of the various families of 

 Lepidoptera, the minor distinctions which are in general use 

 being omitted, and the families numbered from the bottom 

 upwards in what seems to be the most natural order of 

 arrangement : — 



A. Hind wing with 12 veins as in the fore wing and united to the fore 



wing by a jugum 1. Microj)terygidce. 2. HepiaUdce. 



B. Hind wing with not more than 8 veins and retained in position by a 



frenulum or an expansion of the base of the costa. 



Fore wing with vein 1 c present. 



3. Limacodidce. 4. ZygcenidcB. 



5. Castniidce. 6. MegalopyfjidcB. 



7. Psychidce. 8. Heterogynidce. 



9. Cussidce, 



Fore wing with vein 1 c absent *. 



Fore wing with vein 5 fi-om the middle of the discocellulars, the 

 other veins given oti' from the cell arising at nearly even dis- 

 tances on each side of it. 



13. SesiidcB. 14. Tineidce. 



15. Alucitidcp,. 16. Tterophoridce. 



* Except in some genera of Tineidse, such as Methypsa and Tortrico- 

 morpha. 



