102 Dr. H. Eltringham on Specific and 



material and data, and I fear the present effort is no 

 exception. The results may, however, serve to indicate 

 the directions in which future workers, and especially those 

 with facilities for making breeding experiments, may hope 

 to obtain more definite results. For the opportunity of 

 examining and dissecting many rare forms I am indebted 

 to the generosity of Lord Rothschild, Mr. W. J. Kaye, and 

 the Authorities of the British Museum, whilst my friend 

 Professor Poulton has assisted me with his continual 

 encouragement and valuable suggestions. Mr. Kaye has 

 also given me much practical help in sorting specimens 

 and in correspondence, and my friend Dr. F. A. Dixey 

 has rendered valuable assistance in connection with Pierine 

 mimics. Dr. Karl Jordan has kindly looked over most 

 of my microscope preparations and given me the benefit 

 of his views thereon. 



Opinions may differ as to the significance of conclusions 

 based on the structure of the male armature. However 

 that may be, probably most naturalists will agree that close 

 resemblance in these structures may usually be regarded 

 as evidence of near relationship, whilst distinct and con- 

 stant differences will probably generally be accepted as 

 evidence of specific separability. 



In the genus Acraea it was found that in nearly all cases 

 the species were well defined, and anatomical differences 

 easily recognised. Such is only partially the case in 

 Heliconius, as will be seen later, nor are the structures 

 particularly constant within the limits of the same species. 

 It should be understood at the outset that I do not put 

 forward the present paper as a statement of conclusive 

 and final results, hence it is not to be taken as a complete 

 revision of the genus. I do not consider that our know- 

 ledge of the forms is yet adequate to such a task. My 

 desire has rather been to indicate the directions in which 

 future effort should be made, and the lines on which, 

 especially, those in the field might profitably direct their 

 observations. 



The genus is distinguished from Eueides by its much 

 longer antennae. It can be divided, as Riffarth has shown, 

 into two great sections. On the underside of the male 

 fore-wing, from the inner margin to the first branch of the 

 median, is an area which presents a peculiar silky grey 

 appearance. In Section I of the genus this silky surface 

 is continued right up to the median without any visible 



