298 Insects and their Surroundings 



1. HoLARCTic : including Europe, North Africa, North and 



Central Asia, Canada and the Northern United States. 



2. Oriental: including India, Southern China, the Indo-Malayan 



district (eastward to Celebes). 



3. Ethiopian : including Africa south of the Sahara. 



4. Mascarene : Madagascar and neighbouring islands. 



5. Australian : Papua, Australia, New Zealand, and Pacific 



Islands. 



6. Neotropical : including South and Central America, and the 



West Indies. 



7. SoNORAN : including the greater part of the United States 



with Northern Mexico. 



Many groups are confined to one or other of the 

 Zoological Regions, three sub-families of Nymphalid 

 butterflies — the Heliconiinae, the Brassolinae and the 

 Ithomiinse being peculiar to the Neotropical ; such have 

 probably been developed and specialised within the 

 Region and have never occurred elsewhere. An im- 

 mense number of genera are confined to each of the 

 various regions, the Neotropical being the richest in 

 peculiar forms, and the Oriental next. As most insects 

 have the power of flight and often travel great distances, 

 a certain amount of overlapping between the faunas 

 of two neighbouring regions is to be expected. 

 Several typically Ethiopian forms range northwards 

 into Syria, while a species of the characteristic 

 tropical Nymphaline genus, Charaxes inhabits the 

 shores of the Mediterranean. Over a large tract 

 in North America, insects of the Holarctic fauna 

 common in the Old World intermingle with Sonoran 

 forms altogether peculiar to the New. Many typically 

 Oriental genera spread eastward through Papua to 

 New Caledonia and Northern Australia. 



Insect-groups afford many examples of discon- 

 tinuous distribution. Moths of the family Uraniidae 

 occur in the Neotropical, eastern Ethiopian, Mascarene, 

 Oriental and Australian regions ; it is specially note- 

 worthy that the two genera which inhabit respectively 



