528 MR. H. W. BATES ON THE LEPIDOPTERA 



Var. 3. Pale orange-tawny ; apical part of the fore wing dusky, with a large irregular 

 fulvous spot in the centre. 

 Ega. 



Var. 4. Dark orange-tawny ; apical part of the fore wing black, with a series of short 

 narrow isabella-coloured stripes accompanying the nervures ; hind wing having a 

 series of blackish stripes extending from the central macular vitta to the marginal 

 lunules. 

 Ega and St. Paulo. At St. Paulo this was the prevailing form of the species. These 



dark varieties certainly do not inhabit the region of the Lower Amazons. 



Genus Mechanitis (Eab.), Doubleday. 

 Doubld. & Hewits. Gen. Diurn. Lepid. p. 130. 



After a careful examination of nearly all the species, I find that two widely distinct 

 generic types were comprised by Doubleday under Mechanitis. One of these (which 

 comprehends his section 1, including, however, M. Polynmia, placed in Ms section 2) is 

 closely allied to Ceratinia, Sais, Napeogenes, and Itliomia, agreeing with them in the 

 shape and position of the palpi and the rudimentary condition of the fore legs of the 6 ; 

 the other (in which the fore tibiae and tarsi of the <S are nearly of the same shape as in 

 Danais, being only a little shortened, more or less, according to the species, and the 

 terminal joint of the palpi does not project in front of the forehead) approaches Olyras, 

 Tithorea, and Eutresis. This group (Doubleday's sect. 2, in part) I shall name Ilelincea ; 

 the other (sect. 1) will retain the name of Mechanitis. We have here an illustration on 

 a smaller scale of the same deceptive analogy which has led to the junction of the 

 Heliconinse with the Seliconia-like Danainse. There is, in truth, a very wide difference 

 in structure between Mechanitis and Melincea ; but the great similarity in dress of the 

 respective species, in great part pair by pair, has led to their being grouped in one genus. 

 The distinguishing characters of Mechanitis are the following : — 



Head small; palpi thinly clothed with scales, terminal joint pointed, projecting. 

 Antennse moderately long, thickened into a distinct club at the apex. Hind-wing lower 

 discocellular nearly in a line with the median, rather short ; middle discocellular at 

 right angles with the lower, angulated, and emitting a recurrent nervule in the middle 

 in both sexes ; upper discocellular in the 6 inclined towards the base, joining the sub- 

 costal not far from the middle of its course, in the ? very short or entirely wanting, 

 in the latter case the upper radial being as a branch of the subcostal beyond the cell. 

 Costal nervure amalgamated with the subcostal for nearly half the length of the wing in 

 the S . Fore legs of the c? with the femur short, tibiae and tarsi reduced to a small 

 knob ; in the ? slender, the tarsi filiform, the spines minute. 



The genus, as thus defined, comprises two groups of species of very different general 

 appearance, — one containing M. Polt/mnia and its allies, distinguished by their large size, 

 opake wings, and varied coloration — the other including M. Fhi/llodoce of Hiibner, and 

 several nearly related species, remarkable for their much smaller size and pale, semi- 



