HYMENOPTERA. 4/ 



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

 nervures ferruginous ; the scale of the peduncle is subquadrate, 

 its upper margin notched in the middle ; on each side of the notch 

 it is rounded, and the lateral angles are produced into short spines. 

 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 antennse and 

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

 of the tarsi, ferruginous ; in other respects it closely resembles 

 the large worker. 



155. FORMICA SENEX. B.M. 



Female. Length 4.} lines. Opake-black : abdomen slightly 

 shining, with an obscure aeneous tinge ; the mandibles, antenna? 

 and legs ferruginous ; the anterior margin of the head slightly 

 ferruginous. Ilead, of the same width as the thorax, slightly 

 excavated behind ; the anterior margin of the clypeus entire ; 

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

 truncate ; wings subhyaline, the nervures pale testaceous ; the 

 apical joints of the tarsi dusky ; the head arid 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 

 posteriorly ; 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 specimens with the head black, and the 

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

 examples have the head fuscous, the thorax and abdomen being 

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

 narrowing behind the eyes into a slender neck ; the antennae 

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

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

 scale of the peduncle incrassate and subconical ; the apical mar- 

 gins of the segments of the abdomen pale testaceous. 



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



