114 BRITISH LEPIDOPTERA. 



Stirps I : SPHINGO-MICROPTERYGLDES. 



The Sphingo-Micropterygid (or as we have sometimes termed it, 

 the Sphingo-Bombycid) stirps is so-called from two of the most 

 characteristic superfamilies it contains, the Sphingides and the 

 MiCROPTERYGiDEs(Eriocephalids), the former, one of the most specialised, 

 the latter, one of the most generalised, of the superfamilies, not only 

 of the stirps, but of all Lepidoptera. 



Although our knowledge is at present very incomplete, there 

 appears to be good ground for including on the same evolutionary line 

 with these superfamilies, several others of considerable size and im- 

 portance. These are all more or less characterised by the following 

 structural peculiarities : — 



(1) The possession of a flat egg (i.e., with the long micropylar axis horizontal, 

 and with a short vertical axis). 



(2) The maintenance of tubercles iv and v, as sub-spiracular tubercles (except 

 in Sphingids, where v becomes pre-spiracular*) ; a tendency for iv and v to 

 become united into a single sub-spiracular wart ; a tendency for i to form a 

 many-haired dorsal wart, and to form, with iii and iv + v, on either side, a 

 transverse row of warts on each segment ; ii tends very strongly (in some families) 

 to become atrophied. 



The Micropterygids {i.e., the Eriocephalids of Chapman) are so 

 remarkable, that they have been separated by Packard into a sub-order 

 equal in value to all other Lepidoptera combined, and thus we get : — 



Sub-order I : LEPIDOPTERA-LACINIATA— including only the Micropteey- 



GIDES. 



Sub-order II : LEPIDOPTERA-HAUSTELLATA :— 



1. Pal^eo-lepidopteea (Pupse-liberae) including only Ekioceaniides. 



2. Neo-lepidopteea (Pupee-incomplefffi, and Pupse-obteetse) in- 



cluding all other Lepidoptera. 



This, however, represents only the separation of what we may call 

 the stranded remnants of the ancestral lepidopterous fauna, and since 

 Chapman remarks")" that "the Zygaenidae (Anthroceridae), Liviacodidae 

 (Eucleidae), and Micropterygidae (Eriocephalidae) form a group which, 

 though the last member is as low as the lowest Tineina and the first 

 as high as the butterflies or Noctuids, has, nevertheless, been evolved 

 on its own lines, from a common source, as a separate branch of 

 Heterocera," we feel quite justified, in spite of the vast gulf that 

 separates them, in retaining these as superfamilies of this stirps, for there 

 are, of course, almost inconceivable breaks between the superfamilies, 

 even of the same stirps, represented (1) in time, by a3ons of years, 

 and (2) in evolutionary development, by the extinction of thousands of 

 connecting groups, which once surrounded the existent groups, and of 

 which we have now no trace, and can only vaguely surmise either 

 their character or relationships. 



Roughly, then, and bearing in mind what has just been said, we 

 may divide the superfamilies of this stirpsj into two groups according 

 to the amount of specialisation they have undergone. We should 

 then get : — 



* In Agdistis iv becomes post-spiracular, and v sub-spiracular, thus differing 

 from any other Plume larvae known to us. 



f Trans. Ent. Soc. Lond., 1894, pp. 335 et seq. 

 + We are well aware that many other exotic superfamilies may belong to this 

 stirps, but having no special knowledge of the early stages of the species of such 

 superfamilies, they have been excluded. 



