ARMY ANTS IN BRITISH GUIANA. 323 



less rounded; postpetiole distinctly shorter, more than twice as broad 

 as long. Claws, especially on the hind legs, conspicuously larger and 

 coarser than in morosus. 



Mandibles more distinctly striolate, their punctures much smaller, 

 less foveolate and less numerous. Surface of head, thorax, and petiole 

 with small, sparse, piligerous punctures instead of the large, shallow, 

 more or less oblique piligerous foveolse of variable size of morosus, so 

 that the surface is smoother and more even. Gaster somewhat more 

 shining, with finer, scattered piligerous punctures. Pilosity very 

 similar in the two species. 



Worker. Very much like the corresponding phase of morosns, but 

 with the occipital margination and ridges as in the soldier. Sculpture 

 also like that of the soldier and differing in the same way from that of 

 the morosus worker. In the large worker the basal tooth of the man- 

 dibles seems to be more frequently developed in the Guiana form. 



Male (Fig. 5b, 9e, 10). Length about 19-20 mm. 



Eyes and ocelli somewhat larger and more convex than in morosus 

 (Fig. 96), the inner orbits of the former more strongly sinuous; 

 antennae and mandibles longer. Petiole with more distinct posterior 

 corners, its sides more depressed and mth sharper borders, its mid- 

 dorsal surface much less concave. Genitalia large, retracted ; stipites 

 large, expanded, subelliptical, articulated with the basal annulus as 

 in Eciion, volsellse slender, apically geniculate and tapering; sagittse 

 longer and stouter, geniculate at the middle and there furnished with 

 an acute dorsal process. Subgenital plate large, trowel-shaped, ter- 

 minating in two large, acute lateral and two small acute median teeth. 



Color much paler than morosus, being rich, reddish brown, usually 

 with a narrow transverse band near the posterior border of each gastric 

 segment, the base of the last segment, the posterior part of the head, 

 two broad parapsidal streaks and an even broader anteromedian 

 streak on the mesonotum, dark brown. These darker markings seem 

 to vary considerably in cUfFerent indi\a duals. Wings much paler 

 than in morosus, resin yellow, darker at the anterior border of the 

 radial cell; veins also resin yellow. Pilosity on the mesonotum and 

 dorsal surface of the gaster distinctly shorter than in morosus. 



Described from numerous specimens taken at Kartabo Point, Brit- 

 ish Guiana. 



In conclusion I list the four species of Chelioynyrmex and their 

 synonymy as I understand it at the present time. 



