448 Piuf. E. B. Poultou on the Mimetic N. American 

 Transition uetwekn astyanax and auchippus . . . 473 



AroYNNIS (SeMNOPSYCHE) DIANA (FEMALE) A TERTIARY 



MIMIC OV LiMENITIS ASTYANAX 474 



LLMKMTIS (A1)KL1'HA)('ALIFORXIOA, TIIK NVMPHALIXE 

 MODKL OF I.LMKXIT18 L01I(,)UINI 475 



The southern Limenitis (Adelpha) buedowi a mimic 

 OP THE Neotropical Adelpiias . • . . . 478 



The Geographical distribution of the western species 

 of Limenitis in N. America 478 



Relation bktween the pattern of L. lorquini ajid that 

 OK the non-mimetic L. weidemeyeri .... 478 



Mimetic resemblance stronger in the southern examples 

 OF lorquini which are geographically coincident with 

 californica 481 



Differences between californica and bredowi are such 

 as to promote a resemblance between the northern 



form and lorquini 482 



(a) The shape of the irhifis ...... 482 



(li) The fulvoiis mark at the nual aiujle of the hiiid-imngs . 483 



(c) llie step-like break in the hand at the yuietion of fore- 



and hind-wings ....... 48.3 



(d) The external border of the hind-xcing hand . . . 484 

 Sliqiiily increased resemblance to the Adelpha pattern 



in the jiost southern examples of bredowi . . . 485 

 Has reciprocal (Diaposematic) mimicry been established 



BETWEEN californica AND LORQUINI ? . . . . 485 



CONCLUSIONS : 



A. The Eastern Section of North America . . 487 



B. The Western Section of North America . . 488 



Introduction. 



The mimetic species of the North American Nyinplialine 

 genus Limenitis (including Basilarchia) superficially re- 

 semble, in the east and north, as suggested by Doubleday 

 (Gen. Diurn. Lep., ii, p. 275), models belonging to (1) the 

 DanaintV and (2) the PapiHoniiiiv : in the west (8) a 

 Nymphaline model generally placed in the South Ameri- 

 can genus Adcl])ha, allied to Limenitis. 



A species of Limenitis, in many respects relatively 

 ancestral and probably resembliog the form from which 

 the mimics arose, still exists in the east, and another in 

 the west. Hence the history of the transformation — 

 probably in every case very recent — can be made out with 

 exceptional clearness. 



The subject will be treated in the order in w^iich the 

 models have been arranged above. 



I desire to thank Dr. F. Du Cane Godman, F.R.S., for 



