184 BRITISH ANTS. 



been arranged by the ants into a sort of circular fortification, or 

 zareba, access to which is obtained by one or two tunnels, not 

 visible in the illustration, and to which a pathway leads from the 

 entrance 25 . 



The following myrmecophiles have been found with Tapinoma 

 erraticum in Britain : 



Coleoptera : Myrmoecia plicata Er. 



Braconidae : Pachylomma buccata Nees. 



Diptera : Pseudacteon (=Phora) formicarum Verrall. 



Collembola : Cyphodeirus ( = Beckia) albinos Nic. 



Subfamily Camponotinae Forel. 



This is the highest subfamily ; it is very extensive and comprises 

 a number of genera only two of which, Donisthorpea and Formica, 

 occur in Britain and very many species. 



The pedicel in these species always consists of but a single segment, 

 the petiole, and the sting is transformed into a small vestigial 

 apparatus, consequently these ants are unable to sting, but some 

 of them produce poison copiously, and can eject it to a considerable 

 distance. 



Their pupae are usually enclosed in cocoons, but are sometimes 

 naked. 



Table of the Genera. 



1 ( Frontal area triangular, distinctly defined ; ocelli distinct . 2 Formica L. 



- 1 Frontal area rounded behind, not distinctly denned, ocelli not distinct 

 \ 1 Donisthorpea M. and D. 



9 



1 f Joints 2-5 of funiculus longer than the succeeding ones ; frontal area 

 J distinctly defined Formica L. 



- I Joints 2-5 of funiculus not longer than the succeeding ones ; frontal 



' area not distinctly defined Donisthorpea M. and D. 



1 C First joint of funici 

 J small ; size mucl 



- j First joint of funi< 

 v organs lar^e : si 7 



funiculus broader than the rest ; external genital organs 

 much smaller than in the $ . . Donisthorpea M. and D. 

 funiculus not broader than the rest ; external genital 

 organs large ; size nearly equal to $ Formica L. 



DONISTHORPEA Mor. and Drnt. 



= Lasius F. (nee. Jurine). 

 Type : Formica nigra L. (Mor. and Drnt., 1915) ; [Mayr, 1861], 



The ants of this genus belong to the purely north temperate 

 fauna, being common to the Palaearctic and Nearctic Regions, 

 and species have been found in the Baltic Amber. 



They do not stand as high on their legs, and are less active than 



