104 BRITISH ANTS. 



it and the lower part the Solenopsis had formed its nest : owing to 

 the position of the stone on a slope, the crack was in direct com- 

 munication with the side of the hill in which it was imbedded, 

 and here a large colony of Formica fusca had settled behind the 

 stone ; not one of the latter, apparently, could have got into the 

 crack, but the Solenopsis had, of course, easy access to the F. 

 fusca." 17 



In June, 1894, Richardson took a dozen workers at Portland 

 under a stone, and he mentions that this stone was situated about 

 half-way between nests of Donisthorpea nigra and D. flava 20 . 



I found a colony (on May 4th, 1904), situated in the side of the 

 cliff at Sandown, which was not connected with any other ants' 

 nest 28 , workers only being observed, and in August, 1908, I dis- 

 covered it at Blackgang Chine at the roots of Arenaria maritima in 

 company with both D. nigra and D. flava, though in some cases 

 the Solenopsis appeared to be alone 27 , and again at Sandown in 

 1909 the workers were abundant with D. nigra in the sides of the 

 cliffs 29 . 



On August 10th, 1913, Crawley and I took five or six workers in 

 a nest of Formica fusca v. glebaria at " Limpet Run " near San- 

 down 34 , the only specimens that could be found, but on August 

 26th, 1913, I discovered a very large colony at Blackgang 34 . This 

 nest was situated at the foot of the cliffs in a large block of green- 

 sand over two feet long by a foot broad, which, when I endeavoured 

 to lift it up, split in two, the whole of the top half coming away 

 bodily in my hands. The surface thus revealed was quite black 

 with the great numbers of males present, and underneath them 

 countless thousands of the small yellow workers occurred. Small 

 chambers had been excavated in the sandstone which contained 

 large numbers of larvae of all sizes, eggs, worker and male pupae, 

 but only one female pupa was found, which was subsequently 

 reared. Only two winged females were observed, and no dealated 

 female could be traced, but as Forel 12 has pointed out the latter 

 are very difficult to find. There was no other ants' nest in the 

 immediate vicinity, and the most careful investigation failed to 

 produce any myrmecophiles or Aphidae among the Solenopsis. 



This little robber ant is subterranean in its habits the workers, 

 which are nearly blind, very seldom coming up above ground 

 and it generally lives in the nests of other species, where it preys 

 on their brood, building small chambers in or beneath their nests. 

 Very fine galleries allow them to gain access to the runs and 

 dwellings of their hosts, these galleries however being far too 

 narrow to permit the entrance of the latter. Forel 10 has com- 

 pared them to mice which live in our dwellings, and Lord Avebury 15 

 has pictured the situation as follows " Solenopsis fugax which 

 makes its chambers and galleries in the walls of the nests of larger 

 species, is the bitter enemy of its hosts. The latter cannot get at 



