Mimetic Relationships in the genus Heliconius. 109 



hitherto regarded as related to the Cydnoformes, the 

 structure of the clasper on PI. XV shows it to belong rather 

 to the Silvan i formes. If it had a denser tuft of bristles 

 it would be difficult to distinguish it from aristiona lenaeus. 



H. ismenius, Latr. 



The typical and four subspecies occur in Colombia and 

 Central America. Though the forms are placed near 

 nurcaea in existing works, I have placed them nearer to 

 the latter part of Section I, since, if the form of the claspers 

 is to be regarded as any indication of relationship, then 

 they are undoubtedly closely allied to the melpomene 

 association. The claspers of three forms are shown on 

 PL XV, from which it will be noted that there is some 

 variation between them. The clasper of " silvana " 

 metaphorus is also shown, and is seen to resemble that of 

 ismenius telchinia so closely that we cannot doubt that the 

 form is much more closely related to ismenius than to 

 silvana. Indeed, I am convinced that it is merely another 

 form of ismenius. 



We have now considered nearly all the reputed species 

 which appear to belong to the group Silvaniformes. Forms 

 of which I have been unable to obtain examples are ennius, 

 sulphureus, and hippola. With so peculiar a genus it may 

 be rash to speculate on the position of forms which have not 

 been examined, but I should expect ennius to prove a form 

 of quitalenus, and sulphureus of ethilla. As to the rare 

 species, hippola, of which only the type seems to be 

 known, its appearance gives no clue. It will, perhaps, 

 prove to be near narcaea. 



Assuming the structure of the genitalia to be of any value 

 at all in these forms, we can, therefore, arrange the reputed 

 species in six groups of which it may be said that if the 

 respective members are not conspecific, at least they are 

 extremely closely allied, and are not separable by any 

 constant and recognisable features of the male armature. 



I have left for consideration at the end of this group 

 two species which are amongst the most remarkable of all 

 the Heliconii. The first is H. tumatumari, Kaye, from 

 Guiana. This species resembles aoede astydamia, forms of 

 erato, and secondarily forms of melpomene. It is a tribute 

 to Mr. Kaye's excellent judgment that he did not regard 

 it as a form of melpomene, but described it as a separate 

 species. The structure of the male armature is quite 



