550 PEOF. E. B. POTTLTO]!T : NATURAL SELECTIOlf 



intruders venture themselves amongst the humhle-bees in a ]ess 

 kindred form, their lives would probably pay the forfeit of their 

 presumption." This interesting paragraph, although fully re- 

 cognizing the utility of mimetic resemblance in species which 

 were then believed to have been separately created and to have 

 come into existence fully formed and complete, sustains a posi- 

 tion which is the very antithesis of that taken up by Bates. The 

 contention that the utility of the resemblance has been the 

 cause of its persistence, and, by the selection of variations going 

 further in the same direction, of its improvement, would have 

 been rejected, probably with indignation, by the distinguished 

 authors of the ' Introduction.' 



Bates's great paper dealt with the fauna of tropical America, 

 and the generalization was manifestly incomplete until it had 

 been extended to other parts of the world. This confirmation 

 was not long in coming, being supplied for the tropical East by 

 A. E. Wallace's paper published in the 'Transactions' of this 

 Society (1866, vol. xxv.), and for Africa by Eoland Trimen's 

 paper, also to be found ia our ' Transactions ' (1870, vol. xxxi.). 

 It is remarkable how completely the Linnean Society has been 

 the medium for the publication of classical memoirs upon 

 Mimicry. Up to the year 1870 it contained them all ; while in 

 1858 it served as the channel through which the parent theory 

 of Natural Selection was first given to the scientific world. 

 The next great advance did not take place until 1879, and was 

 published elsewhere. 



Bates had called attention to certain resemblances which could 

 not be interpreted under his theory of mimicry, viz. the frequent 

 similarity between the specially defended forms themselves. 

 Forms which are themselves the models for mimicry nevertheless 

 mimic or at least resemble other models. For such cases Bates 

 could only suggest the direct action of some unknown local force 

 or forces, and Wallace followed him in this. 



In May 1879 Fritz Miiller published a paper in 'Kosmos'* 

 which for the first time off'ered an explanation, based on the 

 theory of natural selection, of these mysterious resemblances. 

 He suggested that such likeness between dominant forms was 

 advantageous to them, inasmuch as it facilitated tbe education of 

 their enemies, reducing the amount of destruction which must 

 be wrought during tbe time in which young birds and other 

 * "Ituna and Thyridia: a remarkable case of Mimicry in Butterfliee." 



