Explanation of Plate B. 



Ancillary appendages of species of Plebeius to illustrate relation- 

 ships of P. argus {aegon). (See Proc. p. xvii.) 



Fig. 1. Dorsum of P. argus, x 30. 



2. „ „ P. argyrognomon, x 30. 



3. End of clasp of P. argi/rognomon, x 100. 



4. ,, „ P. sci(dderi, x 60. 



5. Dorsum X 20 j ^f P. r«iito,is. 



6. End of clasp, x 60 j 



7. Dorsum X 20 | ^f p. /, arcana. 

 H. End of clasp, x 60 / ^ 



9. Dorsum, X 20 | ^f p f,,res. 



10. End of clasp, x 60 .( ^ 



11 Dorsum X 20 } oi P. haberhanen. 



12. End of clasp, x 60 J 



13. Dorsum, X 20 | ^f p. .iem-*i. 



14. End of clasp, x 60 j 



N.B.^ — Note, in comparing, the greater enlargement of Fig. 3, to 

 show the fine teeth, and that Figs. 1 and 2 are enlarged one and a 

 half times more than Figs. 5, 7, 9, 11, and 13. 



Plebeius deobis and eversmanni are very similar to P. argyrognomon. 

 P. scudderi, melissa, and zephyrus (lycidas) have dorsa something 

 like that of P. argus, but ends of clasps similar to those of the 

 P. argyrognomon group. 



I have not met with any species with ends of clasps more definitely 

 intermediate between those of P. argus and P. argyrognomon than 

 those here figured. 



All these species (with very various macroscopic characters) are 

 rather intermediate between P. argus and P. argyrognomon than out- 

 side them. This is what makes it difficult to believe that the 

 general similarity of those two species shows close relationship and is 

 not ratlier due to approach from similar environment or otlier cause. 

 Except P. lycidas they are the only European species of the genus, 

 the only generally distributed species. 



Plebeius acmon and some others are apparently outside the 



limits marked by P. argus and P. argyrognomon, and there are, 



I need hardly say, a few species I have not had an opportunity of 



examining. 



X . A. U. 



