66 THE NORTH AMERICAN SPECIES OF DROSOPHILA. 
students. In general, the opinion of the most recent student has been 
accepted in matters of synonymy and generic references. 
TABLE 8. 
Species that also 
Total species. occur in other 
regions. 
IPaleareLicmnnicecb ae 
BG HIOPIAM ieee heron siete 
Ornientalam enema: anlar mee: 
INCRE CUIC iss Hey ee sp esee re 
INeotropicaly res eae Rte 
Polynesiane nya. samen eee 
Total, 228, less 26 duplicate 
entries, 202. 



* Includes Australia and New Zealand. 
This list, of course, is an index of the thoroughness with which the various 
regions have been studied, as well as of the number of species actually 
occurring in them. The total of 202 species is certainly far too small. 
Perkins (Fauna Haw., 1, clxxxix) says not less than 250 species of the tribe 
must occur in the Hawaiian Islands alone, and most of these forms appar- 
ently belong to the genus Drosophila itself. All the regions except the 
Palearctic and Nearctic will certainly yield very many more species when 
they are thoroughly collected, and the two regions named are by no means 
exhausted of new species. 
The distribution of the genus within each region is not adequately known, 
but it seems probable that Drosophila is to be found everywhere except in 
very cold regions. The data on the point that I have collected from the 
literature and from my own observation of specimens follow: 
Palearctic: Faroe and Canary Islands to Sweden, Egypt, Chinese Turkestan, and Japan‘ 
Ethiopian: Eritrea to Ashantee, Rhodesia, Mauritius, and the Seychelles. 
Oriental: New Zealand to the Philippines, Java, and India. 
Nearttic: Nova Scotia to British Columbia, southern California, and Florida, Bermuda. 
Neotropical: Florida, Bahamas, and Cuba to Argentina, Chile, and Mexico. 
Polynesian: Tahiti, Hawaii, Fiji. 
D. remota Walker was described from the island of Tristan d’Acunha; 
but, like most of Walker’s species, this can not be accepted until verified. 
There are not very many species of Drosophila common to the nearctic 
and Neotropical regions (only eight). In addition, three Neotropical species 
occur in southern Florida, where Nearctic species are also to be found. 
Since a number of the Neotropical species are imperfectly known, it is 
difficult to place them conveniently in a key. Accordingly two keys have 
been constructed. The first, which is only slightly modified from the one 
already published (Bull. Amer. Mus. Nat. Hist., 38, 443), includes the known 
Nearctic species, and the three Neotropical forms found in southern Florida 
(D. lutzii, D. willistoni, and D. cardini). The second key includes the 
Neotropical forms known from the West Indies (including Trinidad) and from 
Central America (including Panama) and Mexico. 
