234 



BRITISH ANTS. 



not of a very satisfactory character. The typical forms however 

 are very distinct, and it may be as well to tabulate how they may 

 be distinguished here : 



D. umbrata. 



$ Larger, clear yellow ; hairs 

 (bristles) longer and more abundant ; 

 more pubescent. 



Eyes a little smaller and flat. 



Funiculus of antennae thin, with 

 joints longer than broad. 



Scale higher. 



Tibiae with outstanding hairs. 



$ Lighter brown ; hairs longer 

 and more abundant ; more pubescent. 



Head larger, more emarginate pos- 

 teriorly. 



Funiculus thin, with joints longer 

 than broad. 



Scale emarginate at apex. 



Tibiae with outstanding hairs. 



Wings with dark colour not reach- 

 ing so far across ; discoidal cell larger. 



< More robust, less shining and 

 more pubescent. 



Mandibles with more distinct 

 teeth. 



Eyes with outstanding hairs. 



Wings with dark colour not reach- 

 ing so far across ; discoidal cell a 

 little larger. 



D. mixta. 



^ Smaller, brownish yellow ; hairs 

 (bristles) shorter and less abundant ; 

 less pubescent. 



Eyes a little larger and less flat. 



Funiculus of antennae thicker, 

 with joints broader than long. 



Scale lower. 



Tibiae without outstanding hairs. 



$ Darker brown ; hairs shorter 

 and less abundant ; less pubescent. 



Head smaller, less emarginate pos- 

 teriorly. 



Funiculus thicker, with joints not 

 longer than broad. 



Scale not emarginate at apex. 



Tibiae without outstanding hairs. 



Wings with dark colour reaching 

 further across ; discoidal cell smaller. 



$ Less robust, more shining and 

 less pubescent. 



Mandibles with less distinct teeth. 



Eyes without outstanding hairs. 



Wings with dark colour reaching 

 further across ; discoidal cell a little 

 smaller. 



I found several colonies of mixto-umbrata at Wey bridge in 1912, 

 males and winged females occurring with them in numbers in 

 September 5 ; Halle tt has sent it to me from Porthcawl, and specimens 

 I took at Bletchington in May, 1913, might be called this var., as 

 the workers are somewhat intermediate in colour, etc., and the 

 partly winged female has a few outstanding hairs on the tibiae. 

 The two females which were taken in nests of D. aliena at Wey- 

 bridge, and which will be mentioned under mixta, also have a few 

 hairs on the tibiae. It appears probable that the colony recorded 

 by Farren-White in his garden at Stonehouse would also come 

 under mixto-umbrata ; he writes, when speaking of specimens of 

 D. mixta given to him by Bignell : " He kindly furnished me 

 with specimens they are marvellously like Lasius umbratus 

 or Formica umbrata ; the workers and males especially so. The 

 pubescence, however, is not so conspicuous upon the tibiae in the 

 workers and females as in umbratus, and the colour of the females 

 is of a dark sepia brown rather than of a reddish brown or mahogany 

 tint, as in the typical specimens of umbratus. However, I have 

 specimens of L. umbratus intermediate in its degree of pubescence 



