266 BRITISH ANTS. 



punctured than in rufa ; eyes with sparse hairs ; scapes of antennae long and 

 projecting further beyond the posterior corners of the head than in rufa. 

 Thorax a little narrower with the pro- and mesonotum more convex. Scale 

 with golden bristles, more abundant in the Rannoch specimens. Legs more 

 hairy than in rufa, particularly so in the Scotch specimens. Long. 5-5-8-5 mm. 



$ Size and colour much as in rufa ; but more pubescent and hairy. 



Head long, narrow, with straight cheeks ; frontal area duller and more 

 punctured than in rufa ; eyes with sparse hairs ; scapes of antennae project- 

 ing further beyond the posterior corners of the head than in rufa (this is 

 brought about by the shape of the head, as the scapes, when measured, are 

 not longer, and sometimes not so long, as in rufa). Thorax a little narrower, 

 with mesonotum more convex anteriorly ; meso- and metathoracic sternites 

 and epinotum with some long golden hairs. Scale and anterior margin of 

 gaster furnished with long golden hairs ; gaster duller, more closely punctured 

 than in rufa, with the red colour on the anterior portion of the first segment 

 well marked. Legs more hairy than in rufa. Long. 9-5-10-5 mm. 



I have not seen a male, nor a winged female ; the worker is 

 described from Continental and numerous Scotch specimens, the 

 female from eight deflated specimens from Rannoch. The Scotch 

 specimens only differ from the Continental ones in being more hairy. 



Original description of Formica rufa var. alpina Santschi (Bull. 

 Soc. Ent. France 1911 349) : 



" Taille, couleur et pilosite comme chez le type. La tete est beaucoup 

 plus allongee et plus etroite en avant (un quart plus longue que large chez 

 alpina et a peine un cinquieme chez le type). Le scape depasse davantage 

 le bord occipital. Le thorax est plus etroit avec un promesonotum plus 

 convexe. L'abdomen est legerement plus large. Le reste semblable. 



Montagne au Nord de Sondrio (Valteline). Re9ue de M. le Pr. Galli 

 Valerio." 



Santschi says : " To this form ants of other provinces connect 

 themselves by the same character (the elongate head) but of 

 variable colours. This is the case with examples from Munich 

 sent to me by Professor Emery, which have the colour and pilosity 

 of F. truncicola. This made me suspicious that this curious morpho- 

 logical modification might possibly be due to parasitism. Wheeler, 

 Emery, Wasmann, Janet, etc., have already pointed out a 

 dimorphism more or less constant with other ants infested either 

 with entoparasites such as Mermis and Pelodera, which inhabit the 

 abdomen or the pharyngeal glands of the adult, or by ectoparasites 

 living as commensals at the expense of the larvae 1 ." 



On June llth, 1911, I found at Rannoch, on the edge of a moor, 

 a small mound made of heather, etc., which was superficially very 

 like a nest of F. exsecta, the workers running about on the mound, 

 according to the habit of that species, were mostly small in size 

 and very red in colour, and might have easily been taken for it, nor 

 were there any tracks to and from the nest such as are found with 

 F. rufa. On examining the workers they were at once seen not to 

 belong to exsecta, and the nest being dug up four deflated females 

 were found to be present. Having come to the conclusion that it 

 was a form new to Britain I sent specimens to Forel and he wrote 



