332 BRITISH ANTS. 



possess large water-holding cells, between the green chlorophyl 

 cells, and that when the leaves dry up the former cells fill with air, 

 which gives a white appearance to the whole hillock 37 . 



Adlerz 38 says that F. picea appears to have completely adapted 

 itself to a life in the sphagnum swamps of Nordland, outside of 

 which he has never met with it, and he describes their nests as 

 follows: "In the sphagnum mounds inhabited by F. picea are 

 passages and chambers dug out so compactly that their arrange- 

 ment recalls that of the masonry nests of the species of Lasius. 

 The excavated material is partly spread over the surface of the 

 mound, thus increasing the size of the hillock, partly used for the 

 partition walls between the chambers. These partitions are com- 

 posed of a pliant, felted mass of shredded sphagnum interwoven 

 and held together by a white, ramified fungus, which is of entirely 

 different appearance to that of Cladotrichum myrmecophilum grow- 

 ing in nests of Lasius fuliginosus." 



He says in fine weather the pupae are placed immediately under 

 the outer covering of the chambers, and he has found the ants, their 

 larvae, and pupae in the lower parts of the nest, which could be 

 best compared to a completely saturated sponge, from which the 

 water ran upon the slightest pressure ; and that if the hillocks be 

 opened, the ants often seek refuge by plunging under the surface 

 of the water, holding firmly on to the moss, swaying it, evidently 

 of set purpose, and pressing it down into the water until it closes 

 over them, in order to hide in the already inundated chambers of 

 the lower parts. 



In his experience the pupae are as often naked as enclosed in 

 cocoons, and if, as often asserted, the object of the cocoon is to 

 protect the pupa against damp, then one would expect to find in 

 these sphagnum nests, if anywhere, exclusively pupae in cocoons. 

 Protection against dry weather appears to be unnecessary in these 

 moss hillocks, so that the occurrence of cocoons among the picea 

 pupae cannot be satisfactorily explained on these grounds. 



Adlerz says that the males and winged females first appear at the 

 beginning of August, and that he has found picea workers as slaves 

 in sanguinea nests. He also found fly larvae (Microdon) in these 

 nests. 



On June 17th, 1914, I again visited Matley Bog in the hopes of 

 finding nests of F. picea large enough to photograph for this work, 

 but in this I was disappointed, though I was fortunate enough to 

 find two incipient colonies of this most interesting species. 



Search was first made in the spot where Crawley and I found 

 the ant in 1912, but here it was all too dry, so proceeding further 

 into the bog, I at last found a few workers, running about, arid 

 foraging on a patch of wet sphagnum some distance away. Some 

 were on grass stems and others running on the surface of the sphag- 

 num carrying flies, the body of a small bee, etc., and often when 



