350 TlIK PLACE OF MIMICRY . 



Thus. too. traces of the scalloped border are almost 

 invariabU' retained b)' the mimetic species oi Hypolimnas, 

 and a Heliconine can nearly always be distinguished at 

 a elance by the short radiate white lines on the black 

 border of the hind wing under side. These take the 

 j)lace of roundish white spots which occupy the same 

 position in the Ithomiine model. 



It is possible that simple and easy means of discrimina- 

 tion such as those described in thc^ last paragraph may 

 facilitate recognition between the sexes (see p. 358). But 

 whatever be the value to the s[)ecies, their persistence is 

 a far greater difficulty on the Batesian than on the 

 Mlillerian Hypothesis. 



13. Classes of Facts which have Recoil iy bcoi Urged in 



Siipporl of the Batesian Hypothesis. — INIany arguments 



have been given in favour of the Mlillerian as opposed 



to the Batesian interpretation of Mimicry, and now two 



counterbalancinor considerations remain to be discussed. 



a. Jhitlerjlies ExJiibiting Minietic Resemblance on the 



Upper Surface of the Wings and Procryptic Defence 



071 the Under Surface, 



Instances of this interestincr combination of methods 



are rather rare, the chief examples being found in a single 



Sub-Family in the Old World and a single genus in the 



New. Other instances belonging to the Nyniphalinae:\rQ, 



however, not uncommon. Dr. Dixey considers that the 



same combination is to be found in several Pio'inae, e.g. 



in the crenera Teracolus and Eronia} 



In the tropical American Nymphaline genus Protogonius 

 the whole of the species or sub-species are imperfect but 

 undoubted members (as regards the upper surface) of the 

 princijjal Ithomiine-centred S}naposematic combinations 

 of their respective localities. They reproduce roughly 

 but clearl)- the characteristic elements of the pattern 

 whatever they may be : the barred black and tawny 

 pattern of Central America and Venezuela, the over- 

 spreading yellow of Trinidad, the darkened hind wing 

 of the Guianas, the yellow hind wing stripe and white fore 



' For Mimicry in llie latter genus see Proc. E?it. Soc.^ Lofid., 1906, 

 pp. XXX, xxxi. 



