THE c;anai)1AN entomologist. 227 



Lepidoptera go, there is no case where a natural genus does not show its 

 distinctive characters in the preparatory stages, either in all of them, or 

 part. There is no more natural genus than Colias, and it seems to me 

 enough that the differences in the imagos should be indicated by groups 

 merely. A group may stand for a sub-genus, but the differences in Colias 

 are hardly enough to make sub-genus of. Therefore, I do not approve 

 of the genus Megonostoma, created by -Reakirt in 1863 to accommodate 

 Eurydice and Ccesonia, and a supposed species called by Mr. Reakirt 

 Helena, but which is a variety of one of the others. Mr. Reakirt was, at 

 that date, a zealous collector, but, like myself, was but a beginner, and 

 undertook to generalize in this case on very slight grounds. His most im- 

 portant character for the new genus consisted " in peculiar appendages, 

 found on the middle and posterior legs of the female," to which he gives 

 the name Eupronychia. ''To be found on the under side of the tarsi, 

 respectively, at two-thirds and three-fourths of their length, as two small 

 membraneous appendages, each being tri-jointed." And nearly a whole 

 page of the Proc. Ent. Soc, Phil., Vol. II., is devoted to a description and 

 elaborate measurements of those appendages, running into the hundred 

 thousandths of a millimeter. Now, I never was able to find in any 

 example of Ccesonia or Eurydice any such appendages, and I recollect 

 very well that at the time this genus was made known, another lepidop- 

 terist said the appendages were merely spiculae from some flower, pro- 

 bably of Asclepias. Recently I made a fresh examination and have 

 found nothing, though I have a great many females of these species to 

 make examination of. Desiring the observations of some one besides 

 myself, I wrote Mr. E. M. Aaron, at Phil., asking him to subject 

 examples to the action of a powerful microscope. He replied : " After a 

 careful examination of a number of specimens, I fail to find anything that 

 will answer to Reakirt's Eupronychia. It would seem that this charac- 

 teristic is worthless, at least. The microscope used is a most powerful 

 one." In the other characters cited by Mr. Reakirt — as eyes, oval, pro- 

 jecting, &c., &c. — there is nowhere a generic distinction. Eurydice and 

 Ccesonia have falcate fore wings, but that is not a generic difference, else 

 Papilio Rutulus would have to be separated from P. Turnus. Between 

 the imagos of these two species and Euryt/ieme and Philodice are 

 resemblances which bind them closely together, and which can have come 

 only from a common ancestor : as the discal spots, the sub-marginal points 

 on under side, the spots at base of hind wings, and the patches at outer 



