March, i8 3 8.] GROTE : CLASSIFICATION OF LEPIDOPTERA. 11 



Agliadas (the Citheroniadae especially). For the moment we will con- 

 sider and compare the Endromid and Sphingoid wing. The vein on 

 costal edge of primaries (vein I) present in the Hawk Moths is absent in 

 Endromis. This vein (or thickening, according to some of the costal 

 edge) is found in the Hesperian^ but not, so far as I know, in the Para- 

 philias. The most striking difference between Endromis and Sphinx, 

 is found in the evident effort in the former to get rid of vein III 2. 

 This springs from the Radius, near IIIi, in the Hawk Moths. In En- 

 dromis it is absorbed and appears as a short branch before apex.* This is 

 a secondary character, belonging to the general direction of a diminution 

 in the normal number of the radial veins. This direction has appar- 

 ently been followed out and brought to a higher stage throughout the 

 Saturniades. But the inequality of its expression is here no indication 

 of the phylogeny, seeing that it is every where exhibited in different per- 

 fection and upon different lines of descent. It is my second direc- 

 tion in the general evolution of the lepidopterous wing. 



In my first direction,^ the suppression of the Media, Endromis has 

 progressed further than Sphinx. For the cubital direction of vein IV2, 

 often only indicated in the Hawk Moths, here becomes assured and evi- 

 dent. The crossvein already shows signs of degeneration. The wing, 

 in broadening, has lost the strength requisite to sustain swift and pro- 

 longed flight. There is, in Endromis, a less crowding of the veins ; 

 they do not appear so like rigid and parallel rods. There is a larger 

 space between the Cubitus and vein VII, so that VI there appears as a 

 fold in the membrane. Both families retain VIII as a loop to VII on 

 primaries, and there is no trace of other internal veins. On secondaries 

 vein VIII is equally preserved. Looking at the two wings I am met 

 with no character which renders it unlikely that they may have had a 

 common origin. Here is where positive character may be said to end 

 and where the tact and experience of the observer comes into play. 

 But, on the threshold of this disputable region, I can yet point to the 

 intercostal vein and throw the onus of proof on those who dispute the 

 classification. As between Endromis and Sphinx there is no question 

 which has submitted to most specialization in the neuration. In both 



* In Amphidasys betularia the absorption of III2 by III 1 is clearly seen to be 

 in process of being carried out. 



f Perhaps we should call this rather the "second direction," seeing that the sup- 

 pression of the radial veins is used as a primary divisional character of the Suborder, 

 but in the lepidoptera, as we find them now, the breaking up of the median system 

 excites everywhere the chief interest. 



