160 BRITISH ANTS. 



and both females rested on it, eggs were laid and the ants all lived 

 together in amity. The affinis queen died on January 21st, 1913, 

 but the nylanderi queen and a number of workers which are 

 however nearly all nylanderi and larvae are still under observation 

 (March, 1914). Workers may often be seen to carry their fellows, 

 when the one that is carried is held by the jaws with the dorsal 

 surface uppermost, above the body of the carrier. Two nylanderi 

 queens, workers, and brood, obtained near Ipswich in October, 

 1914, were introduced into this affinis-nylanderi nest. Some fight- 

 ing took place at first, but no deaths occurred ; the bulk of the 

 new ants remaining by themselves in one chamber of the nest. 

 After three months they were found to have amalgamated with 

 the old inhabitants, and become one colony, which is still under 

 observation. 



In 1906 I took a large worker (3 '5 mm. in length) of Leptothorax 

 nylanderi in a nest of Donisthorpea fuliginosa at Wellington College 

 which has the head more rounded than in the ordinary worker, the 

 gaster longer, and banded as in the female ; evidently a similar 

 intermediate form to those before mentioned under L. acervorum. 



Leptothorax corticalis Schen. 



Myrmica corticalis Schenck Jahrb. Ver. Naturk. Nassau 8 100 (1852) 1 . 

 Leptathorax corticalis Mayr Verb Zool. Bot. Ver. Wien 5 440 (1855) 2 . Myrmica 

 (Leptothorax) corticalis Schenck Jahrb. Ver. Naturk. Nassau 16 197 (1861) 

 < 3 . Leptothorax tuberum r. corticalis Forel Denkschr. Schweiz. Ges. Naturw. 

 26 85 4 227 5 (1874). Leptothorax tuberum var. corticalis Er. Andre Spec. 

 Hym. Europe 2 298 (188 1) 6 . Leptothorax corticalis Dalla Torre Cat. Hym. 

 7 123 (1893) 7 . Leptothorax tuberum Vic. Hist. Berks. 1 76 (1906) 8 . Lepto- 

 thorax tuberum subsp. corticalis Crawley Ent. Rec. 24 63 (1912) 9 ; Crawley 

 and Donisthorpe Int. Ent. Cong. Oxford 1912 2 19 (1913) 10 ; Crawley Ent. 

 Rec. 26 92, 95, 106 (1914) 11 . 



$ Reddish brown, mandibles, antennae, articulations of the legs, and tarsi 

 reddish yellow, femora and tibiae red-brown, head above and first segment of 

 the gaster dark brown. The colour is sometimes lighter as in a specimen before 

 me from Munich. 



Head finely striate ; clypeus as in tuberum ; antennae twelve-jointed. 

 Thorax finely striate, but more rugose than in nylanderi, without a distinct 

 impression between the mesonotum and epinotum ; epinotal spines very 

 broad at base, horizontal, very short, scarcely as long as a third of the basal 

 face of the epinotum. Pedicel finely striate ; gaster smooth and shining. 

 Legs without erect hairs. Long. 2-5-3-2 mm. 



$ Dark brown, mandibles, antennae and legs yellow-red. 



Head longitudinally striate ; clypeus as in tuberum ; antennae twelve - 

 jointed, club no darker than the rest of antennae. Thorax : mesonotum and 

 scutellum finely striate longitudinally ; epinotal spines short. Pedicel finely 

 striate ; gaster smooth and shining. Long. 3-5-4 mm. 



<J I have not seen a typical male ; Schenck's description will be 

 found below, and Crawley describes a male in the British Museum 

 collection from Naples labelled " corticalis var." as follows : 



" Joints 2-5 of funiculus much longer than broad. Head rugose ; meso- 

 notum smooth and shining between the converging lines ; pedicel slightly 



