136 SMITH ON HYMENOPTERA OF AEU ISLANDS. 



2. Formica gracilipes, Smith, Cat. Hym. Ins., Journ. Proc. Linn. Soc. ii. 

 p. 55. 13 ^ . 



3. Formica fragilis. F. pallide testacea, elongataet gracilis, capite 

 postice angustato ; thorace medio compresso, pedibus elongatis ; 

 squama incrassata triangulata. 



Worker. Length 3^ lines. Pale rufo-testaceous, smooth and slightly 

 shining ; antennae elongate, longer than the body, the flagellum slen- 

 der and filiform, the scape nearly as long as the h£ad and thorax ; 

 head oblong, narrowed behind the eyes into a kind of neck, the sides 

 parallel before the eyes, which are black and round, the clypeus slightly 

 emarginate anteriorly, the mandibles finely serrated on their inner 

 margin and terminating in a bent acute tooth. Thorax elongate, 

 narrowest in the middle, the prothorax forming a neck anteriorly ; 

 legs elongate and very slender. Abdomen ovate, the node of the 

 petiole incrassate, and viewed sideways is triangular or wedge-shaped. 

 Hub. Aru. 



This is one of those remarkable forms which recede so greatly from 

 the normal type of Formica as apparently to indicate a generic distinc- 

 tion ; but in those exotic species of which we have obtained all the forms, 

 we find many which approach closely to the present insect, which is 

 probably only the small worker of some already described species. No 

 one would venture, without the authority of the personal observation of 

 some competent naturalist, to unite all the forms of any exotic species of 

 Formica. 



4. Formica flavitarsus. F. nigra, elongata et gracilis; thorace 

 postice compresso, pedibus elongatis, tarsis flavis. 



Worker. Length 4 lines. Black and sub-opake ; head elongate, nar- 

 rowed behind, the clypeus truncate anteriorly, the mandibles pale fer- 

 ruginous ; antennae elongate and slender, the flagellum filiform and 

 pale rufo- testaceous ; the thorax and legs elongate, the latter slender 

 with their tarsi pale rufo-testaceous. Abdomen ovate, the scale of the 

 petiole incrassate and slightly notched above. 



Hab. Aru. 



5. Formica coxalis. F. nigra, nitida; flagello, coxis et abdomiue 

 subtus pallide testaceis. 



Worker major. Length 5 lines. Black and very delicately roughened 

 with a fine transverse waved striation only perceptible under a good 

 magnifying power. Head large, much wider than the thorax, oblong- 

 ovate with a deep emargination behind ; the clypeus slightly produced 

 and truncate anteriorly, the angles of the truncation rounded, and 

 with a central shining carina ; the flagellum, except the tarsal joint, 

 pale rufo-testaceous. Thorax elongate, compressed behind, the coxae 

 pale rufo-testaceous. Abdomen ovate, the scale of the petiole in- 

 crassate, somewhat wedge-shaped when viewed sideways, the abdo- 

 men sparingly sprinkled with long pale hairs. 



