695.78 15 



The Classification of the Day Butterflies 



IN classifying the day butterflies systematists have availed them- 

 selves of external characters, as a rule without subjecting these 

 to a test, by way of ascertaining their comparative value. Now, 

 each organ, or part of an insect, presents taxonomic character rela- 

 tively stable and primary, and again relatively unstable, recurrent, 

 or adaptive and secondary. It is a peculiarity of the secondary 

 characters that they engage the attention, only in the end to dis- 

 appoint our efforts to use them in establishing a system, — one which 

 shall not constantly leave exceptions upon our hands to be accounted 

 for otherwise than by the system itself. 



There exists, also, the prevalent belief, that there is really a 

 structurally more advanced leader to that host of butterflies which 

 is always pressing forward out of the future to appear in the present 

 and vanish into the past, and that the rank and file of the butterfly 

 phalanx emulate this favoured one, or its type, in structural perfec- 

 tion. A direction in the specialisation of this or that organ — yes ; 

 an ultimate goal which all are alike striving to attain and in which 

 some are merely outstripping the others — no. Eank must always 

 remain a relative conception, and, to avoid a confusion of ideas, it is 

 better to substitute for it, in natural history, the terms sjjecialisation, 

 as denoting advanced, and generalisation, as signifying retarded 

 development of organic features. 



We can illustrate what we mean by taking up one or another 

 of the systems which have been put forward as an arrangement of 

 the day butterflies, and no better one can present itself than that 

 advocated by Mr Scudder in his boolc on the ' Butterflies of New 

 England ' and elsewhere. Here the Satyrids, or ' Meadow Butter- 

 flies,' are placed ' at the head ' (to use the characteristic phrase of 

 the Philadelphia Check List), while the ' Swallowtails ' are inserted 

 between the ' Blues ' and the ' Skippers.' That, through this pro- 

 ceeding, Mr Scudder has been led into the mistake of separating 

 two groups, which belong phylogenetically together, by the interpola- 

 tion of a third, not at all nearly related to either, we expect to 

 prove. The mistake would seem to have been committed by Mr 

 Scudder through a want of discrimination between adaptive or 



