2 NUMBER OP SPECIES. 



are known. Even this large number is certainly far 

 short of those actually in existence.* 



I have kept in captivity about half of our British 

 species of ants, as well as a considerable number of 

 foreign forms, and for the last few years have generally 

 had from thirty to forty communities under observation. 

 After trying various plans, I found the most convenient 

 method was to keep them in nests (see fig. 2, p. 43, 

 and Plates VI. and VII.) consisting of two plates of 

 common window glass, about ten inches square, and at 

 a distance apart of from ^^ to ^ of an inch (in fact just 

 sufficiently deep to allow the ants freedom of motion), 

 with slips of wood round the edges, the intermediate 

 space being filled up with fine earth. If the interval 

 between the glass plates was too great, the ants were 

 partly hidden by the earth, but when the distance 

 between the plates of glass was properly regulated with 

 reference to the size of the ants, they were open to 

 close observation, and had no opportunity of conceal- 

 ing themselves. Ants, however, very much dislike 

 light in their nests, probably because it makes them 

 think themselves insecure, and I always therefore 

 kept the nest covered over, except when under actual 



• I have had some doubt whether I should append descriptions 

 of the British species. On the whole, however, I have not thought 

 it necessary to do so. They are well given in various entomological 

 works : for instance, in Smith's Cat. of Bntish Fossorial Hymen- 

 optera, published by the Trustees of the British Museum ; Saunders' 

 ' Synopsis of British Heterogyna,' Trans. E7vto'inological Soc. London; 

 and in Mayr's Die Uiirop. Formiclden, all of which are cheap and 

 easily procurable, I have, however, given figures of the principal 

 species with which I have worked. 



