vi RHOPALOCERA HELICONIIDES 351 



Sub-Fam. 7. Heliconiides. Submedian nervure of front wing 

 not forked ; 'median with a short spur near the base. Cell of hind 

 wing closed by a perfect nervule. Palpi compressed, with scales at 

 the sides, in front covered with hairs. Male ivith an elongate 

 unjointed, female with a four-jointed, front tarsus. Caterpillars set 

 with branched spines. This family is peculiar to tropical America 

 and consists of only two genera, Heliconius and JEueides, with 

 about 150 species ; but it is one of the most characteristic of the 

 South American groups of Butterflies. It is very closely allied to 

 the Nymphalides, especially to the genera Metamorpha and Colaenis, 

 but is readily distinguished by the perfectly-formed nervules that 

 close the wing-cells. The wings are longer and narrower than 

 in Nymphalides, and the colour, though exhibiting much diver- 

 sity, is on the whole similar to that of the heavily-scaled forms 

 of Ithomiides of the genera Tithorea, Melinaea, Melanitis ; there 

 being in several cases a great resemblance between species of the 

 two groups. A frequent feature in one group of Heliconius is 

 that the hind wing bears a patch of red prolonged outwards by 

 angular radiating marks. The individuals of certain species H. 

 melpomene and H. rhea are known to execute concerted dances, 

 rising and falling in the air like gnats ; when some of them 

 withdraw from the concert others fill their places. H. erato 

 exhibits the very rare condition of trichroism, the hind wings 

 being either red, blue, or green. Schatz states that the different 

 forms have been reared from a single brood of larvae. The cater- 

 pillars of Heliconiides live on Passiflorae, and are said to be very 

 similar to our European Argynnis-caierpillnrs. The chrysalids 

 are very spinous. We may here remark that considerable con- 

 fusion exists in entomological literature in consequence of Itho- 

 miides having been formerly included in this sub-family ; for 

 remarks formerly made as to " Heliconiides," but that really 

 referred only to Ithomiides, have been interpreted as referring 

 to Heliconiides of the present system. 



The Heliconiides seem remarkably plastic as regards colour, 

 and are therefore exponents of " homoeochromatism." Bates 

 says, as regards them : " In tropical South America a numerous 

 series of gaily-coloured butterflies and moths, of very differ- 

 ent families, which occur in abundance in almost every locality 

 a naturalist may visit, are found all to change their hues and 

 markings together, as if by the touch of an enchanter's wand, at 



