HYMENOPTERA. 4? 



line with the vertex of the eyes ; the wings are subhyahne, their 

 nervurcs ferruginous ; the scale of the ])e(lunck' is subquadrate, 

 its u))per inargui notched in the middle ; on each side of the notch 

 it is rounded, and the lateral angles are ])roduced into short sj)ines. 

 We have seen, from the collection of Mr. Swainson, an ant which 

 we suppose to be the small form of the worker; it differs from 

 the large form in having the head narrower, the antennae and 

 mandibles, as well as the clypeus anteriorly and the apical joints 

 of the tarsi, ferruginous ; in other resj)ects it closely resembles 

 the large worker. 



155. Formica senex. B.I»I. 



Feiuale. Length 4 Mines. — Opake-black : abdomen slightlv 

 shining, w ith an obscure a'neous tinge ; the mandibles, antenme 

 and legs ferruginous ; the anterior margin of the head slightly 

 ferruginous. Head, of the same width as the thorax, slightlv 

 excavated behind ; the anterior margin of the clvi)eus entire ; 

 the apex of the llagellum dusky. Thorax ovate, the metathorax 

 truncate ; wings subhyalinc, the nervurcs pale testaceous ; the 

 apical joints of the tarsi <lusky ; the head and thorax are deli- 

 cately shagreened, have a few scattered shallow punctures, and 

 are sprinkled with erect white hairs. Abdomen ovate ; the 

 node of the peduncle ovate, margin entire ; the abdomen is thinly 

 covered with short white hairs, the margins of the segments 

 ciliated with longer ones. 



Worker. Length 3 lines. — In colour agreeing with the female. 

 Head wider than the thorax. The thorax short, slightly narrowed 

 ])osteriorly ; the metathorax quadrate above and truncate behind ; 

 the scale as in the female, and the insect sprinkled with white 

 hairs as in that sex. 



Hab. Rio (Constancia). (Coll. Rev. H. Clark.) 



156. Formica Agra. B.M. 



Worker. Length 5^-6 lines. — Elongate, slender; very vari- 

 able in colour, some sjjecimens with the head black, and the 

 thorax and abdomen dark brown, the legs being jjaler; other 

 examples have the head fuscous, the thorax and abdomen being 

 of a reddish -brown, tlie latter with the apex darker. Head widest, 

 narrowing behind the eyes into a slender neck ; the antennie 

 long and slender ; the prothorax elongate, much narrowed an- 

 teriorly ; the legs elongate and slender. Abdomen ovate ; the 

 scale of the ])eduncle incrassatc and subcorneal ; the apical mar- 

 gins of the segments of the abdomen i)ale testaceous. 



Hab. Rio (Petropolis) ; Columbia. (Coll. Rev. II. Clark.) 



