32 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



family is provided. Vein 7 is quite close to 8, and parallel with 

 it, until it reaches a point near the hump, where it curves down- 

 ward, approximating 6, with which it is usually connected by a 

 cross vein, and then slants upward toward the outer extremity 

 of the -costa. The extra vein, when present, may be found aris- 

 ing out of 7, just under the hump, or at times connected by a 

 cross vein with 8. In most of the later forms however this extra 

 vein has disappeared. The changes which take place in the vari- 

 ous genera, when a degradation of the neuration takes place 

 in the hindwing, are apparently quite simple. The extra vein is 

 usually the first to be lost, followed by 4 and then usually by 3, 

 although sometimes 3 appears rather to become transformed into 

 a continuation of 2. Of the branches 5 and 6 it is probably 6 

 that is the first to disappear. The median vein (5, 6) and 7 tend 

 to approximate one another until they may culminate in the form 

 found in Phyllonorycter, and its allies, and anastomose anteriorly. 



In the forewing there are several features which are thought to 

 be particularly noteworthy. In Acrocercops, Parornix and 

 Parectopa it will be seen that the position of 11 is, at the point 

 of its origin, much farther removed from the base of the cell, and 

 that the system of veins 10 to 7 is much more advanced along 

 the costal margin of the cell, than is the case with Gracilaria. 

 In the latter 10 arises much nearer the base than 2 while with 

 the former genera the contrary is the case. There seems to be 

 in the later development, in this family, a crowding of the veins 

 toward the apex of the wing, and the formation of a more 

 or less pointed outline at the anterior margin of the cell, when 

 any veins have been lost in this region. This may perhaps be 

 accounted for by the fact that in many species possessing a 

 complete neuration the outer wall of the cell is weak. The loss 

 of veins takes place by means of the usual methods, obsolescence 

 or stalking. In the costal series 11 and 7 may disappear by 

 obsolescence or. in the case of 7, by stalking with 8. Of veins 

 8, 9 and 10 no tendency to disappear was noted, that is to say 

 none of these veins was observed while in the act of disappearing, 

 either by obsolescence or by stalking. In the case of several genera 

 with much degraded neuration, where there were no intermediate 

 forms, Meyrick's diagnosis was accepted and vein 8 stated to be 

 absent. In the dorsal series 2, and possibly 6, may disappear 

 by obsolescence. In Gracilaria there is a tendency toward sim- 

 plification by the stalking of 4 and 5, while in Parornix, Parectopa 

 and Acrocercops there is a tendency to simplify by means of the 

 stalking of 6 with 5 or 7, and accompanying it the loss of veins 

 2 or 3. " 



It may be stated that the venation of Apophthisis Braun could 

 not be studied, owing to .lack of material, and that it is placed 



