OF THE AMAZON VALLEY. 529 



transparent wings. These latter may retain as sectional distinction the name Oleria, as 

 proposed by Hiibner. 



Section 1. Oleria, Htibner. 

 Hiibner, Verzeichniss bekannter Schmetterlinge, p. 9. 



1. Mechanitis (Olebia) theaphia, n. sp. 



Very similar in size, shape, and general appearance to Mechanitis or Ithomia ethica 

 (Hewits. Exot. Butt. Ithomia, fig. 140). 



c? ? . Expanse 1" 2"'-l" 8'". Wings pale sulphur-white, semitransparent. Eore wing 

 with a wide border, and a broad oblique band extending from the costa across the end 

 of the cell to the outer margin near the hind angle, black ; a submarginal row of round 

 white spots in the outer black border, not reaching the hind angle. Beneath, the same. 



Hind wing with a black border, narrow on the costa, and broad along the outer 

 margin, the latter having a submarginal row of rounded white spots. Beneath, the same. 



Body and antennse black. Head and thorax with some whitish markings. 



Eound on the banks of the Cupari, a branch of the Tapajos, and also at St. Paulo, on the 

 Upper Amazons. At St. Paulo the individuals were larger and more vividly coloured 

 than on the borders of the Cupari. 



Section 2. Mechanitis proper. 



2. Mechanitis Poltmnia (Linn.), Cramer, Pap. Exot. t. 191. f. E. 



This species, like many others of the Heliconidse, is subject to remarkable local 

 variation. The varieties, taken in connexion with their geographical distribution, 

 are a most interesting study. The species is extremely abundant wherever it is found, 

 and the different varieties are copiously represented in collections. It is slow in 

 flight, and inhabits thinned parts of the forest, or neglected and shady plantations near 

 settlements. The caterpillar (figured in Sepp, Papill. de Surinam, pi. 2.) has a smooth 

 integument. The head is round, and the body has a row of small pointed tubercles on 

 each side. It is grey, with black spots, and ringed with yellow. It feeds on Solaniim 

 aculeatissimwn, and is gregarious. The chrysalis is smooth. 



The typical form of the perfect insect, as figured by Cramer, prevails at Para and 

 throughout the Lower Amazon region. All the examples collected at the different 

 stations in those parts resemble each other pretty closely in colours and markings. At 

 Ega, on the Upper Amazons, the species is very unstable ; very few individuals were 

 found conformable to the Cramerian type : it there varies, not only in general colour 

 and pattern, but also very considerably in the shape of the wings, especially in the male 

 sex. One variety seems, however, to predominate, to which I give the name of M. 

 Egaensis : I frequently found pairs of it in copula, and never observed it to mate with 

 other varieties, from which I was inclined to conclude that the individuals preferred to 

 pair with their exact counterparts, and therefore that the variety was in process of 

 segregation from the type. All the intermediate forms between the typical M. IPolymnia 

 and M. Egaensis occurred at Ega, but in fewer numbers. At St. Paulo, 260 miles 



4 B 2 



