THECLA. 



American species of Lycsenidae, for which it has been so freely used. Fabricius includes 

 eight species in Thecla, of which he names three, T betulce, T. spini, and T. quercus ; 

 and it is only by considering T. spini the type that the species with two subcostal 

 branches can be called Thecla, T. betulm and T. quercus having three such branches. 

 Hewitson restricted Thecla to the two-branched section, and placed in it several 

 hundred South-American species, with a large number of which we now have to deal, 

 as well as with many additional ones. So long as the genus Thecla remains undivided, 

 the convenience of the application of the name in Hewitson's sense is obvious, and we 

 continue its use as heretofore. We have seriously considered the question whether or 

 no the genus should be divided into a number of genera, and this, at first sight, would 

 seem to be the proper course ; but on looking closely at the gradual modification of 

 nearly all the available characters, we have come to the conclusion that if divisions be 

 once commenced they would have to be carried to such an extent that the result would 

 be far more confusing than the present state of things. Hubner, the great genus- 

 maker of his day, undoubtedly proposed many names for genera now included under 

 Thecla by Hewitson ; but his combinations are by no means satisfactory, though these 

 names may be made use of under some future arrangement ; but we cannot too strongly 

 urge that nothing should be attempted in this direction without an examination of 

 carefully-prepared specimens, and not in the rough-and-ready method usually adopted. 

 We have made many such preparations, which have enabled us to examine several 

 points with great minuteness ; they have served to show us that many more are 

 necessary before an adequate knowledge can be obtained for satisfactorily grouping 



the various species. 



As we have already dealt with the main features of the genus Thecla in our notes 

 under the head of Lycsenid®, it remains to state approximately the number of species 

 comprised in the genus, though it is difficult to make an exact estimate. Mr. Kirby's 

 final Appendix, published in 1877, gives the number 541, and a good many species 

 have been added since that ; so if we place their present number at 600 or 700, we 

 probably shall not be far wrong. Of these about twenty belong to the Old World. 

 About forty species are found in the United States, some of which occur also within 

 our borders. We have therefore about 550 species in the Neotropical Eegion, as far 

 as our present knowledge goes, a number which will probably be largely increased by 



future research. 



Within our own country we now recognize about 209 species which are widely 

 distributed over the whole area, though their numbers are doubtless far greater in the 

 hotter districts, for in Northern and Central Mexico, which still remain to be searched, 

 there are comparatively few. 



biol. cente. amee., Rhopal., Vol. II., May 1887. 



