Larvae of Membracis serving as Milk-cattle to a 

 Brazilian Species of Bees 1 ). 



With 4 Figures. 



My letter in Nature, vol. viii. p. 201, was incomplete so far as the names of 

 the Brazilian insects alluded to are concerned, but I am now enabled accurately 

 to name both the supposed milk-cow and the supposed milker. With regard to 

 the former, Mr. Rogenhofer, of Vienna, has had the kindness to compare my 

 specimens of Membracis with the collection in the museum of that metropolis, 

 and informs me that my Membracis belongs to the genus Potnia of Stal ( Umbonia 

 of Fairmaire), the species most probably being indicator Fairm. As to the Trigona 

 species referred to in the above letter, I have in the meantime received numerous 

 good specimens, not only a number of workers, but also some males, and even 

 one queen. Mr. Frederick Smith has been good enough to compare my specimens 

 with the collection in the British Museum, and has found that they belong to an 

 undescribed species. Having worked through the literature on Trigona and Meli- 

 pona as completely as possible, and after perusing the descriptions of about one 

 hundred species, not having found a single one of wich all three kinds of indi- 

 viduals are known, I think it will be welcome to the readers of this journal who 

 are interested in entomology, if I do not restrict myself to merely mentioning the 

 name and diagnostics of my new Trigona species, but give a description of its 

 workers, male and queen, adding a brief account of its peculiar habits and economy 

 from my brother's (Fritz Muller) observations. 



Trigona cagafogo 2 ). 



Length of the workers and males 5 ^/ 2 , of the queen 6 7 mm. Males and 

 workers are almost alike in size, colour, and outline of the body, and are distin- 

 guished from most other species of the same genus by the breadth of their head 

 and the narrowness of their abdomen, which, in the workers, scarcely exceeds half 

 the breadth of the head. In the males the abdomen is equally slender, but the 

 head somewhat less broad; in the queen the head is of the same size and form 



1) Nature, a weekly illustrated Journal of Science. Vol. X. 1874. PS- 3 1 3 2 - Published by Her- 

 mann Muller, Lippstadt. 



2) I call the species Cagafogo, using the vernacular name for the specific one. 



31* 



