DIURNAL LEPIDOPTERA. 75 



from the Pierids, on account of the close resemblance of the cater- 

 pillars of the two groups ; their position far removed from the other 

 brush-footed butterflies is intended to mark their anomalous structure, 

 while their slight elevation above the Erycinids signifies the nearly 

 equal development of the fore legs in both sub-families. The Par- 

 nassians resemble the Lyctenids in the egg state, and to a certain 

 extent the Erycinids in their larval state, and are therefore turned 

 toward the Gossamer-winged butterflies, though belonging closely with 

 the Swallow-tails. The resemblance of the egg of the Hesperides and 

 Pierids on the one hand and of the smaller skippers and Swallow-tails 

 on the other is shown by the direction of the branches of the lowest 

 family. By this scheme, all the spinous caterpillars are brought to- 

 gether upon one side, and near together, and all the heteropodous 

 butterflies are carried above the middle. 



It may be remarked that, with slight variations, this distribution 

 of the groups of butterflies, founded upon the relative perfection of 

 their organization is generally accepted by the best investigators; and 

 is founded upon a mass of minor features which will not be recounted 

 here. A single exception should however be made in regard to the 

 typical butterflies, whose position is the point of greatest dispute, many 

 continuing to place them highest of all on account of the beauty and 

 special perfection of character of a single member of that family, the 

 group of Swallow-tails. Nothing can exceed the gorgeousness of the 

 huge Ornithopteras of the ICast Indies, and the most queenly of our 

 own butterflies are their nearest relatives. They also show a unique 

 development, as has bjen thought, in the diminutive size of the palpi 

 of the imago, in the possession of four branches to the median nerv- 

 ure of the front wing, and in the dorsal and extreme development of 

 osmateria in the caterpillar. But there is no reason whatever for con- 

 sidering the brevity of the palpi or the extra branch of the median 

 nervure marks of high organization. On the contrary, in these very 

 points they resemble the skippers more closely than they do any other 

 butterflies, and these features are therefore traces of their low organ- 

 ization. Indeed the terminal median nervure of the Swallow-tails is 

 the most unstable in its attachments of all the nervules of the fore 

 wing; it appears to belong decidedly to the median nervure only in 

 the Swallow-tails, but there can really be no doubt that it is a part 

 of the same nervure in the skippers; while in the Nymphales it has 

 simply transferred its allegiance to the sub-costal nervure ; and if it 

 exist at all in the Rurales, which we doubt, it is the nervule usually 

 connected with both nervures by an equally obsolete vein, but be* 



