OF THE AMAZON VALLEY. 
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transparent wings. These latter may retain as sectional distinction the name Olcria, as 
proposed by Hiibner. 
Section 1. Oleria, Hiibner. 
Hiibner, Verzeichniss bekannter Schmetterlinge, p. 9. 
1. Mechanitis (Oleria) theaphia, n. sp. 
Very similar in size, shape, and general appearance to Mechanitis or Ithomia ethica 
(Hewits. Exot. Butt. Ithomia, fig. 140). 
<* ? . Expanse 1" 2"'-l" 8'". Wings pale sulphur-white, semitransparent. Fore 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 spot •>. Beneath, the same 
Body and antennae 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 t lie 
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 Heliconidae, is subject to remarkable local 
variation. The varieties, taken in connexion with their geographical distribution, 
are a most interesting study. The species ;s 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 Solarium 
aciileatissimnm, and is gregarious. The chrysalis is smooth. 
The typical form of the perfect insect, as figured by Cramer, prevail* at Par& 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 m 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. Folymnm 
and M. Egaensis occurred at Ega, but in fewer numbers. At St. Paulo, 260 miles 
y 4b2 
