BEES IN THE COLLECTION OF THE UNITED STATES 

 NATIONAL MUSEUM.— 3.1 



By T. D. A. COCKERELL. 



0/ the University of Colorado, Boulder. 



Having spent some weeks in Washington, arranging the exotic 

 bees in the National Museum, I found it necessary to set aside a large 

 number of undetermined species for farther study. The neotropical 

 fauna especially is represented by large collections which prove to 

 contain many new and little-known species. The museum at the time 

 of my visit contained about 460 determined species from south of 

 the Mexican boundary (including the West Indies), but when the 

 undetermined material has all been classified the number will prob- 

 ably be not less than 700. Various parts of the Old World are also 

 represented by collections which add considerably to our knowledge 

 of distribution and include forms new to science. 



The present j)art includes the neotropical social bees of the genus 

 MeUpo7ia. These insects, as also the species of the allied genus 

 Trigona^ present a great number of races or very closely allied 

 species, as do the ants. The group of Melipona fasclata, for example, 

 with its local forms in Brazil, British Guiana, Trinidad, Panama, 

 Costa Rica, etc., recalls the condition found among the ants of such 

 a genus as Caniponotus. The several forms are also related to one 

 another in much the same degree as the "representative species" in 

 the islands of an archipelago, as the birds of the Galapagos Islands 

 or the Lesser Antilles. The natural inference is that this production 

 of numerous closely allied forms is not due primarily to anything 

 peculiar about the variability of social bees or ants, but comes about 

 as a by-product of isolation. It appears probable that thb mating 

 sexes of these insects almost always come from the same nest, so that 

 the several colonies give rise to others through a process of inbreed- 

 ing. The tendency under these circumstances is toward a homo- 



* For previous papers In this series see Proc. U. S. Nat. Mus., vol. 39, 1911, pp. 035-658, 

 and vol. 40, 1911, pp. 241-264. 



Proceedings U. S. National Museum, Vol. 55— No. 2264. 



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