the Gcomctvina of the European faunn. 70 



though probahly once extensively prevalent, it has been 

 driven out by hi,Q;her forms, and only scattered frag- 

 ments remain. Some of its more ancestral genera are 

 amongst the most primitive forms of the Geometrina, 

 and make a near approximation to the Notodontidte, but 

 the European genera are all amongst the later developed. 

 The larvae are little known, but some at least have a 

 third pair of claspers, and sometimes show rudiments of 

 the other two pairs. 



In the normal and characteristic type of structure 

 vein 5 of the hind wings is present, and 8 free and 

 closely approximated to cell from near base to beyond 

 middle ; this type occurs in no other family of the group. 

 In two European genera (and also in one Australian, 

 otherwise remote from them) 8 anastomoses with upper 

 margin of cell quite as in the TIi/driomenichB, but the 

 absence of the characteristic neuration of the fore wings 

 of that family immediately distinguishes them, and 

 there is not, in fact, any near relationship. In one of 

 these same genera (Phthorarcha) , a degenerate type, 

 vein 5 of the hind wings is absent ; from a comparison 

 of the closely allied Erannis, it appears that this vein is 

 coincident with 4, and not obsolescent, as in the Selido- 

 scmidfB, where the vein is really present but reduced to 

 a fold ; there is therefore no real confusion with that 

 family, from the normal type of which Phthorarcha is 

 further distinguished by the anastomosis of vein 8. In 

 three or four genera there is a very short fusion or 

 anastomosis of vein 8 with upper margin of cell near 

 base ; these may be immediately distinguished from the 

 StcrrhidcB by vein 8 remaining for some distance nearly 

 approximated to upper margin of cell, instead of rapidly 

 diverging, and by the absence of the characteristic 

 neuration of the fore wings. 



In this family the antennae are very frequently uni- 

 pectinated in the <? ; nearly three-fourths of the species, 

 including the most dissimilar forms, show this structure, 

 which is very rare in other Geometrina, and, indeed, 

 amongst the Lepidoptera generally, but as it happens, 

 none of the European genera are so characterised ; this 

 is an indication of their less primitive nature. 



