No. II.— HYMENOPTERA, APOIDEA. 



By T. D. a. Cockerell, Professor of Systematic Zoology, University of Colorado. 

 (Communicated by Prof. J. Stanley Gardiner, M.A., F.R.S., F.L.S.) 



(Text-figures 1 — 3.) 

 Read 1.5th June, 1911. 



The interesting series of bees brought together by Mr Hugh Scott shows that the 

 islands of the Indian Ocean are by no means so poor in these insects as the previous 

 scarcity of records might have suggested. The present paper deals almost wholly with 

 the species of two groups, the Seychelles and Aldabra, including with the latter Assumption 

 Island. 



The Seychelles bee-fauna may be divided into groups as follows : 



(1) Endemic species, apparently without close relatives elsewhere : Sphecodes scotti, 

 Halictus mahensis. 



(2) Endemic or precinctive species and subspecies, very closely allied to those found 

 elsewhere. These may be again divided into 



(a) Species of Holarctic affinities : Ceratina nodosiventris, C tabescens. 



(h) Species of African affinities : Mesotrichia incerta seychelleiisis. 



(c) Species of Indo- Pacific affinities : Lithurgus scotti. 



(3) Wide-spread species, perhaps introduced by man : Megachile disjuncta, M. 

 rufiventris, M. seychellensis, Apis unicolor. The case of Megachile seychellensis is 

 peculiar. In its typical form, it is known from the Seychelles and Farquhar, but it has 

 a small race in Aldabra. The Hawaiian M. palmartini is almost identical. Thus we seem 

 to have a widespread insular type, with slightly differentiated species or races. 



The absence of any distinct Indian element will be noted. 

 The Aldabra fauna may be similarly divided : 



(1) Endemic species, very distinct: Halictus aldabranus, Ceratina fi-yen. 



(2) Endemic or precinctive species and subspecies, very closely allied to those found 

 elsewhere : 



(a) Species of Holarctic affinities : Halictus nicolli, Heriades aldabranus. 



(b) Race of Seychelles species : Megachile seychelleiisis aldabrarum. 



