NOTES AND LITERATURE 



Diptera from the Seychelles. — An important work has just 

 come to hand 1 in which Mr. C. G. Lamb describes the muscoid 

 flies of several groups, collected in 100.") in the Seychelles and 

 other islands of the Indian Ocean by the expedition under the 

 leadership of Mr. J. Stanley Gardiner. Considering the remote- 

 ness of the regions explored, and the total lack of general inter- 

 est in the taxonomy of these small Diptera, one would not at first 

 see any reason for calling special attention to this paper. When, 

 however, we think of the wonderful results attained by Morgan 

 and those working with him through the intensive study of 

 Drosopliila, Mr. Lamb's work, dealing in part with this very 

 group, gains new significance and suggests many strains of 

 thought. Some years ago. a iVr looking at a number of the strange 

 Drosophila mutants in Professor Morgan's laboratory, I raised 

 the obvious question: "How do you know that all this has any- 

 thing to do with the evolution of species?", and Professor Mor- 

 gan replied that he did not know it. The real answer to my 

 question must be found by investigating the allied species, to see 

 whether they do in fact differ in ways at all paralleled by Mor- 

 gan's mutants, or likely to have arisen in similar fashion. The 

 important cytological paper by Metz, just published, represents 

 one way of attacking this problem; the taxonomic results of 

 Lamb, based on twenty species, afford us another. 



At the outset, Ave are struck by the fact that the Seychelles 

 Drosopliila species have been modified in a great variety of dif- 

 ferent ways, in several cases so remarkably that Lamb hesitates 

 whether to base new generic or subgeneric names upon them. 

 There is nothing like orthogenesis, apparently. Here is a list of 

 some of the more noticeable modifications: 



1. Costa extending to third vein. 



2. Remarkably constricted waist and short wings. (Compare 

 Morgan's short winged forms.) 



3. A remarkable slit on the costa, the end provided with spines 

 and bristles. 



4. Remarkable transverse or oblique eyes. 



5. Remarkable spines on front tarsus. 



I Trans. Linnean Sec. London, Zoology, Vol. XVI, Part 4, July, 1914. 

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