374 
, INSECTAj LEPIDOPTEllA. 
is known of the fauna of the interior of Australia ; that of the 
north coast is entirely Indian ; and, indeed, the Australian fauna 
is merely a branch of the Indian. Koch then remarks on some 
of the peculiarities of Australian forms. The entire Old-World 
fauna forms one great whole ; but for convenience it may be di- 
vided into the European and the Indian, the first corresponding 
with Sclater^s Palaearctic Region, and the second including the 
whole of the remainder. 
5. The American or Transatlantic fauna, characterized by the 
genera Papilio^, Euterpe, Leptalis, Pieris,Myscelia,Catagramma, 
Callicore, Perisoma, Heterochroa, Morpho, Caligo, Euptyckia, 
Hcetera, Neonympha, Theda, Castnia, Glaucopis, Euchromia, 
Hyper ddria ; also the families Heliconidce, Erycimdce, and 
Hesperiidce, The American fauna is distinguished by its rich- 
ness, containing more species than all the other quarters of the 
world put together, only the Indian fauna at all approaching it. 
It straggles to the north as far as Baltimore, where it passes into 
the European fauna. Still the fauna of the United States and 
California has a character peculiar to itself, which it does not 
lose till we arrive at the circumpolar fauna. It is probable that 
if a chain of islands similar to the Indian archipelago extended 
across the Atlantic in the temperate zone, the North-American 
fauna would be richer in European forms. The principal 
characteristic genera found in South America are then enu- 
merated. 
Probably, if Europe lay less to the north, the only two faunas 
which could be distinguished would be the western and the 
Transatlantic ; and the common origin of all the Lcpidopterous 
faunas of the world is shown by the frequent coexistence of the 
same genera, distinguishable at a glance, in several or in all the 
widely separated regions of the earth. {Cf. De Borre, Ann. Ent. 
Belg. xiii. pp. xx-xxiv.) 
Maassen (S. E. Z. 1870, pp. 49-62) has published a critical 
analysis of Keferstein^s ‘ Betrachtungen gekniipft an meine 
Schmetterlingssammlung ^ (S. E. Z. 1869, pp. 191-230; Zool. 
Bee. vi. pp. 346, 347). After pointing out the fallacies in 
KefersteiiPs calculation of the probable number of Lepidoptera 
existing in the world, he attempts to estimate the number him- 
self, by taking the pYoportion of 26 moths to one buttcrlly, which 
he finds to exist in all approximately complete local lists in Eu- 
rope. He also estimates the total number of Lepidoptera in the 
world to be 26 times as large as in Europe. Speyer (Linn. Ent. 
Bd. xii.) estimated the probable number of Lepidoptera at 
130,000. \_Cf. Bates, Tr. E. Soc. 1869, p. xlviii, who estimates 
them at 227,400, instead of 129,744, which is Maassen^s total.] 
* Papilio is much better represented in the Indo-Australian region than in 
America. See Wallace’s essay on the Malayan Papilionidcc. 
