658 THE PANORPOID COMPLEX, in., 



Eocicada (c) which, in the extreme reduction of its hindwing, 

 is the most heteroneurous form of all. 



(3) As regards the manner of branching of Rs in the fore- 

 wing, this comes closest to that of the Hepialidae in Prolystra 

 and Palaeontina; but in the former of these R 1 is missing, and 

 in the latter it is much reduced. Both, then, stand in advance 

 of the Hepialidae. In the other genera, the method of branch- 

 ing of Rs, if correctly restored, is highly specialised, and most 

 certainly not of the Hepialid type. 



(4) In the forewings of all the genera, Cu 2 is a complete 

 vein, whereas it is reduced in Hepialidae. Further, Eocicada 

 shows the unique specialisation of having Cu 2) moved distad be- 

 yond the secondary cubital fork, an extraordinary character 

 which at once places this genus as far removed from any 

 existing type of Lepidoptera. 



The forewing of Palaeocossus (Text-fig. 84, a) seems about 

 as closely allied to that of Prolystra (d) as is that of Palaeon- 

 tina; but it differs from both these latter in having lost the 

 original dichotomic manner of branching of Rs. 



To sum up, then, it would appear that the Jurassic Palaeon- 

 tinidae form either a family, or a group of allied families, of 

 distinct heteroneurous venational type, but not related to any 

 existing Heteroneura. They are best regarded as a special line 

 of development from the old Homoneurous stem of the Order, 

 which have died out without leaving any direct descendants at 

 the present day. They should not be included in the Hetero- 

 neura as at present defined, but may be regarded as an isolated 

 side-branch, under the name Palaeontmoidea . 



Family COSSKLE. 



This family includes both the Zeuzeridae and the Cossidae 

 (or Trypanidae) of some authors. Turner has done a valuable 

 service in establishing the essential unity of these two groups, 

 which Meyrick, for instance (3), placed widely apart on very 

 insufficient grounds. The venational schemes of all the known 

 genera are figured in Turner's fine paper (32) . 



For the study of this family, I have to thank Mr. Luke 

 Gallard for a large supply of larvae of the two genera Xyleutes 

 and Culama. Unfortunately I did not succeed in keeping any 

 of the latter alive until they pupated, although I had them for 



