104 BRITISH LEPIDOPTERA. 



have had access to all the leading papers on this subject, Corn- 

 stock, Hampson, Kellogg, etc. 



The conclusions to which we have come concerning the characters 

 considered by various authors as important may be briefly stated as 

 follows : (1) The jugum. — As Chapman has already pointed out, this 

 is" the remnant of a wing-lobe, well developed in many Neuroptera, 

 and appears to have no such function as is attributed to it {i.e., of com- 

 bining the wings in flight) . ' ' The hindwing of Micropteryx (Eriocrania) 

 has " also an external lobe or ' jugum ' " (Packard). The classificatory 

 value of the jugum, by which Comstock separates the whole order Lepi- 

 doptera into Jugate and Frenate, therefore, is such as to shut off the 

 two or three most generalised superfamilies, such separation giving us 

 no clue whatever to the more specialised superfamilies that have risen 

 from the stirps, of which these are now the lowest representatives. 

 (2) The frenulum. — Chapman has pointed out that one of the super- 

 families (Micropterygides) placed with the Jugate, has also distinct 

 traces of a commencing frenulum in the development of some strong- 

 hairs ; whilst Kellogg findsf in the Trichopterygid genus Hallesus, 

 "the beginning of the frenate method of Aving-tying," there being 

 " present, on the base of the costal margin of the hind-wing, two long, 

 sti'ong hairs, the very counterpart of the generalised frenulum (i.e., 

 frenulum in which the hairs are not united into one single strong 

 spine) of the lepidopterous wing." That the frenulum had its origin 

 much lower than is usually assumed, e.g., in Trichoptera, and, there- 

 fore, probably in Lepidoptera, before they were differentiated as such, 

 leads us to suppose that, possibly in the earlier Lepidoptera (now ex- 

 tinct), many frenate and jugate families, otherwise closely related, ran 

 on side by side. Of the latter, only the Micropterygids, Eriocraniids, 

 and Hepialids are left, and these, although retaining this primitive 

 trait, have become greatly modified in other directions. It seems some- 

 what forced to attempt to derive the Frenate directly from the existing 

 Jugate, now that Kellogg has shown that the frenulum in a 

 generalised form also exists in Trichoptera. That it has always been 

 a very variable and plastic structure, is evident from its present erratic 

 occurrence and absence in allied species. So uncertain is its occurrence 

 that, in order to carry out Comstock's division of the Lepidoptera (ex- 

 cept Jugate) into Generalised-Frenatje and Specialised-Frenat./E, 

 other characters (chiefly from neuration) have to be called in. (3) Neu- 

 ration. — It is now generally accepted that the most generalised super- 

 families exhibit the most complicated system of neuration, and that 

 the more reduced in number the nervures become, the more specialised 

 is the family, superfamily, etc. This, with certain limitations (unneces- 



* During the progress of this work through the press, a change in the usual 

 nomenclature of this gcoup has been made. The genus Micropteryx, Hb., is now 

 said to be synonymous with Eriocephala, Curt., and therefore the superfamily 

 Micropterygikes of this chapter = the superfamily Eriocephalides of Chapter I. of 

 this book. It has also been pointed out that Eriocrania, Zell., is the only name avail- 

 able for the genus that has been until now called Micropteryx. The superfamily name 

 Erioceaniides will, therefore == the Micbopterygides of Chapter I. of this work. 

 Micropteryx and the Micropterygides will, in the following part of this work, refer 

 to the "calthella group," i.e., to the imaginal pollen-eaters and larval moss-feeders ; 

 whilst Eriocrania and the Ebioceaniides will refer to the " purpurella group," with 

 leaf-mining larvse and pupas with active jaws. 



f American Naturalist, 1895, p, 715. 



