an Essay on the British JFormicida. 28 1 



The species named " unifasciata " in British collections is not 

 that which continental authors consider to be Latrielle's species, 

 and in one respect it hardly agrees with his description — the 

 abdomen is fuscous, with the base and apex pale ; in the species 

 which represent iinifascia in the collections of Nylander, Mayr, 

 &c., the abdomen has a narrow ring on the basal segment, and 

 the club of the antennae is fuscous ; the latter species I have not 

 yet seen captured in this country. It may, however, be in some 

 collections mixed with M. Nylanderi. 



Subdivision 4. (Stenamma, Westw.) 



Stenamma, Westw. Intro. Class. Ins. ii. p. 266. (1840.) 

 Formicoxenus, M.a.yr, Form. Austr. p. 141. (1855.) 



The maxillary palpi 4-jointed ; the labial palpi 3-jointed ; man- 

 dibles dentate ; the worker and female with the second node of 

 the petiole spined in front beneath ; the club of the antennae 

 3-jointed ; the anterior wings with the marginal cell open, incom- 

 plete ; one complete subraarginal cell, and one discoidal cell. 



Sp. 10. Myrmica IFestrvoodii. 



Stenamma Westwoodii (Steph.), Westw. Intro. Class. Ins. ii. 



p. 226, ^ . 

 Formicoxenus nitidulus, Mayr, Form. Austr. 146, 1. 

 Myrmica nitidula, Nyland. ; Myrmica Iceviuscula and debilis, 

 Foerster. 



Worker. — Pale rufous, smooth and shining, the head of a 

 deeper colour, more or less, above; the antennae 12-jointed, with 

 the club rufo-fuscous, the tip paler ; the metathorax with a smooth 

 central depression on each side, furnished with a stout tooth 

 directed horizontally backwards ; abdomen nigro-piceous in the 

 middle ; the first node of the petiole with a cariniform process 

 beneath ; the second node with a stout spine at the base pointing 

 forwards. Length l^ lines. 



Female. — This sex differs only in having the ocelli distinct, the 

 thorax more ovate, the wings hyaline, and the stigma fuscous. 

 Length 2^ lines. 



Male. — Nigro-fuscous, the mandibles tridentate ; the antennae 

 1 3-jointed ; the legs pale; the femora more or less fuscous; the 

 metathorax with two short erect teeth ; the wings of a milky white- 

 ness ; the nervures scarcely discernible ; the entire insect thinly 

 sprinkled with pubescence. Length 2 lines. 



VOL. IV. N. S. PT. VII. — APR. 1858. U 



