OF THE AMAZON VALLEY. 565 



Fig. 3. Leptalis Theonoe, var. Lysinoe (Hewitson. Described by this author as a distinct species. The 

 white fore part of the hind wing is merely a sexual character, and is hidden by the fore wing in 

 the natural position of the wings). — Ega, Upper Amazons, 65° W. long. 



Fig. 3 a. Sialachtis Phadusa, var. Duvalii (Perty). — Ega, Upper Amazons, 65° W. long. 



The resemblance between these two is very great, when flying in their native woods. The 

 Leptalis is quite unlike any Ithomia found in the whole region, and is supposed to have been 

 adapted to the Stalachtis, because its original variations were in the direction of Sialachtis, and 

 this disguise equally well served the purpose of preservation with that of an Ithomia. 



Fig. 4. Leptalis Theonoe, var. — Ega. Described by Hewitson as a variety of L. Lysinoe, Exot. Butt. 

 Leptalis, fig. 13. 



Fig. 5. Leptalis Theonoe, var. — Ega. 



Fig. 6. Leptalis Theonoe, var. — Ega. This has considerable resemblance to Ithomia Illinissa, fig. 6 a. 



Fig. 7- Leptalis Theonoe, var. — St. Paulo. 



Fig. 8. Leptalis Theonoe, var.- — Ega. 



Fig. 9. Leptalis Theonoe, var. — St. Paulo. 



These six varieties occurred only in single or very few examples : they imitate (with the 

 exception of fig. 6) no other insect, and are supposed to be either simple variations (sports) or 

 remnants of the steps of modification which have led to the various complete adaptations in the 

 two districts where they are found. In any case (since it is impossible to suppose that each is 

 an unmodified descendant of a parent originally created, in the usual sense of the term) they may 

 be taken as affording proof of the variability of the species in several divergent directions, 

 tending towards resemblance to IthomuB. 



Fig. 6 a. Ithomia Illinissa (Hewits.). — Ega. 



Fig. 10. Dioptis JEliana (n. sp. or var. ?), deceptively like, when flying, Ithomia JElia, a small species 

 near akin to /. Illinissa, and found in company with it at Ega. 



Fig. 11. Dioptis Ilerdina (n. sp. or var.?). Closely resembles, when flying, Ithomia Ilerdina (PI. LVI. 

 fig. 4 a), and found in company with it at St. Paulo. 



Fig. 12. Dioptis Onega (n. sp. or var. ?). Closely resembles, when flying, Ithomia Onega (PI. LV. 

 fig. 2 a), and flies in company with it at St. Paulo. 



Fig. 13. Dioptis Cyma (Doubleday). Closely resembles Ithomia Cymo, a species similar to /. Flo7'a 

 (fig. 1 a of the present Plate), and flies in company with it at Para. 



Plate LVI. 



Fig. 1. Leptalis Theonoe, var. Ery throe. — St. Paulo, 69° W. long. 



Fig. 2. Leptalis Theonoe, var. Erythro'e. — St. Paulo. 



Fig. 3. Leptalis Theonoe, var. Erythro'e. — St. Paulo. 



Fig. 3 a. Ithomia Orolina, var. Chrysodonia. — St. Paulo. 



The linking variations between L. Erythro'e and Theonoe can be traced through the varieties 

 8, 5, and 6 of the preceding Plate. The substitution of red for white in the fore wings is seen 

 to be a simple variation. Some traces of the narrowing of the red margin of the hind wing are 

 also seen. The imitation of Ithomia is not nearly so close as it is in the cases of figs. 1 and 2 of 

 the preceding and fig. 4 of the present Plate, but there is a considerable approximation, giving 

 the appearance of a striving after a correct imitation. The selection of individuals having the 

 most faithful likeness is here either not rigid or we see the formation of an exact mimetic 

 analogue in process. 



Fig. 4. Leptalis Theono'e, var. Leucono'e. — St. Paulo. 



Fig. 4a. Ithomia Ilerdina (Hewitson). — St. Paulo. 



This Leptalis appears at first sight an absolutely distinct species, but it is plainly a modifica- 



