^^^ AND "^^^ 



JOURNAL OF VARIATION. 



Vol. VIII. No. 7. September 15th, 1896. 



Neuration in the Lepidoptera; the study of the wings, nervures, 



shapes, etc. (Illustrated by plate.) 



By AMBROSE QUAIL. 



The development of scales — which protect, and perhaps strengthen, 

 the membrane - has probably had some influence upon the modification 

 of the wing neuration (or system of nervures which strengthen the 

 membrane). From the base of the wings rise five groups of nervures. 

 These nervures sometimes give out branches which are called nervules. 

 Thefivegroups are respectively, see PI. I., fig. 5 (1) Costal. (2) Subcostal 

 or Radius. (3) Discoidal or Media. (4) Median or Cubitus. (5) Sub- 

 median or Anal. There is another nervure which forms the costa, or 

 upper margin of the wings. 



The system of numbering the nervures, by starting at 1 and 

 finishing at 12 or 13, or whatever the total number may be, is useless, 

 in so far as it does not explain the individual value of the nervvires. 

 On p. 18, anU', is an illustration of a system of numbering, "the veins 

 numbered are in accord with the amended system, Redtenbacher — 

 Comstock." In this, the groups are represented by numbers, veins 

 of the fore- wings numbered IV ^ and IV 3 are, however, distinctly 

 attached to III and V nervures respectively, and are in point of fact 

 (IV j^) III5 and (IV3) Vj^, for a reason that I will proceed to explain; 

 the prefix IV indicates the ancestral value (or position) of those 

 nervures. 



It may be well here to give the synonymy of the nervures. The 

 five groups of nervures, mentioned in the first paragraph of this article, 

 are named as follows : — 



I. KiRBY.— (1) Costal. (2) Subcostal. (3) Discoidal. (4) Median. (5) Sub- 

 median. 



II. CoiisTOCK.— (1) Subcostal. (2) Radius. (3) Media. (4) Cubitus. (5) Anal. 

 Personally, I consider the names used by Comstock much more 



appropriate than those used by Kirby, although the latter have 

 probably been much longer in use. 



Modification of neuration goes on in various directions, the radius, 

 median, and cubitus groups become connected by transverse nervules, 

 thus enclosing the median nervure, and forming the discoidal cell. 

 By the strengthening of the radius and cubitus nervures, or, because it 

 is useless (after the formation of the cell), the median (discoidal) nervure 

 becomes weak, and is lost in the higher (most recently evolved) groups 

 of Lepidoptera, although some retain faint traces of it. The median 

 nervules, by a gradual alteration of position, are lost as such, and 



