498 MR. H. W. BATES ON THE LEPIDOPTERA 



There is a very wide dissimilarity in minor jioints and in general appearance between 

 the Asiatic set of forms and the American : the only Old World genus which at all 

 apjiroaches the New World group is Hamadryas ; 1)ut the shape, colours, and neuration 

 of the wings show that it has no close affinity with them. The two sets of forms seem 

 to agree, however, in habits, and apparently occupy the same sphere in the economy of 

 nature in their respective countries. Mr. W'allace, who has had the good fortune to 

 observe l)oth in their native al)odes, says, the habits of the South Asian Euploece (the 

 most numerous genus) are precisely those of the Seliconidoi. The Asiatic Danaklce are 

 mostly above the middle size, and include some of the largest Butterflies known ; their 

 American equivalents are in general below the middle size. Both are extremely prolific 

 or abundant in individuals, and are amongst the most characteristic productions of their 

 respective countries. Each set, also, are the objects of numerous mimetic resemblances 

 on the part of other Lepidopterous insects of their own region belonging to different 

 families, — the Asiatic mimickers being modelled after the Asiatic Danakhv, and the 

 American after the American members of the same family. The entire dissimilarity of 

 the two sets of forms would seem to teach us that there can have been no land com- 

 munication east and west between the tropical parts of Asia and America since they first 

 came into existence, and therefore that the great continents must have remained separate 

 in those quarters from a veiy I'emote epoch to allow for such an extensive independent 

 development of forms. They are both strictly confined to the hottest parts of their 

 respective hemispheres. In America they are not found beyond the northern tropic, 

 nor much further south than 30° S. lat. They are not known to occur so far from the 

 eqviator as either tropic in the Old World, but are limited to the south-eastern parts of 

 Asia and the islands of the New Guinea group. The genus Daiiais, with which we have 

 seen both groups are connected, ranges as far north as 41° in Europe, and 45° in North 

 America. It is interesting thus to find that the only genus which is common to the 

 three tropical regions is the sole one of the family that occurs in high latitudes. The 

 only means of communication l)etween the intertropical lands of America and Asia seems 

 to have l)cen a circuitous route l)y the north (or south) ; and the essentially tropical 

 forms do not appear to have passed ahjug it. The fact of the peculiar equatorial Asiatic 

 DaiKiklce not reaching Africa is explicable on tlie same grounds as their entire distinct- 

 ness from the American ones, namely, the nou-existeace of an equatorial eonnexi(jn ol' 

 land of a nature suitable for their transit l)etvveen the two continents since the remote 

 date when the first forms of the group came into l)eing. 



IMic liabits of the Helicoukhc have l)een described by various travellers, — Lacordaire 

 baviiig given a complete account of the Cayenne species, and Dyson and Gosse some 

 iiit<'i-('stiiig notes on those of Venezuela and Jamaica. The total numl)er of s|)eeies de- 

 sm'ibcd is 2S t, namely, 2',V.i belonging to the Danaoid, and 51 to the AcraH)id group. They 

 ■<m\ j)eculiarly creatures of the forests, and, like tlie Platyrrhine Monkeys, the arboreal 



stomoses with the median a short distance from its origin. In the systematic part of the present memoir I shall 

 follow Dr. Fclder in tiiis altered dassifiration. The two groujis which conqjosed the fiimiU ne/ico/iidti' im; it must be 

 repeated, completely and widely distinct. Yet the analogical resemblance between them is so great, that some si)ecies 

 of the one niiglit easily be confounded (if not closely exaniineil) with speei<'s of the oilier. 



