146 Dr. H. Eltringham on Specific and 



showed a large proportion with heavy black underside. 

 The tendency to melanism was found to be more prominent 

 on the upperside. The author concludes that the forces 

 of selection are now acting more forcibly on the underside 

 pattern, as might be expected from the sedentary habits 

 of the group, and that these forces are now tending to 

 produce forms with less blackening. A further point of 

 great interest was that already mentioned — namely, that 

 all the members of the group are commonly found feeding 

 on the white flowers of Eupatorium macrophyllum, and that 

 whilst there are many other differently coloured forms of 

 Heliconius in the neighbourhood, they are never, in the 

 author's experience, found on these flowers. This point 

 is worthy of special remark as showing how the advan- 

 tages of similarity of pattern may be increased by the 

 development of a common habit. 



In 1908 Mr. J. C. Moulton read a paper " On some of 

 the principal Mimetic (Miillerian) Combinations of Tropical 

 American Butterflies " (Trans. Ent. Soc, p. 585 et seq., 

 1908) in which he described four great associations of 

 mimetic forms, including Ithomiinae, Heliconinae, and 

 members of other subfamilies. Association I is classed 

 as the North Central American type from Guatemala, 

 Honduras, and Nicaragua. The typical pattern is here 

 that of Melinaea imitata, which is closely copied by H. 

 ismenius telchinia, the rest of the group including — ■ 



Ithomiinae 5 

 Danainae 1 

 Nymphalinae 2 

 Heliconinae 1 

 Pierinae 2 

 Hypsidae 1 



Association II is described as the East Brazilian type 

 and is divided into two subgroups (a) having the fore-wing 

 subapical spots yellow and (b) having the same spots 

 white. The first is centred round Melinaea eihra, Godt., 

 and includes H. " silvana " ethra and other species of the 

 following subfamilies : — 



Ithomiinae 4 

 Danainae 1 

 Nymphalinae 2 

 Heliconinae 1 

 Pierinae 1 



