44 PROCEEDINGS OF THE NATIONAL. MUSEUM. vol.81. 



CYPHOMYRMEX COSTATUS. new species. 



Worker. — Length 1.50 mm. 



Head longer than broad, narrowest in front, broadly concave be- 

 hind, occipital corners subangulate ; occiput at middle with a pair of 

 low rounded, longitudinal ridges, parallel to each other ;«nd becoming 

 obselete on the vertex. Cl> pens much longer than ]>road. triangular, 

 nearly flat in front, with the anterior border very faintly concave at 

 middle. Mandibles acute apically, the blades with five short teeth. 

 Frontal lobes nearly flat, each distinctly longer than broad, with the 

 outer border broadly and evenly rounded ; continuous with the carinae. 

 which extend straight and divergent to the occipital border. Antennal 

 scrobes broad and deep, bordered beneath by a low, rather thick ridge 

 which is interrupted at middle by the eye. Antennal scapes short, not 

 attaining occipital corners, very slender at basal third, apical portion 

 strongly incrassate; median funicular joints about twice as broad as 

 long; terminal joint long and strongly narrowed at tip. Pronotum 

 feebly convex, sides with a pair of rounded tubercles in back of mid- 

 dle; humeri obtusely angulate; inferior angles blunt, not spinose. 

 Pro-mesonotal suture not impressed. Mesonotum concave, sides with 

 a rather thick margin, which is shal lowly impressed a little posterior 

 to the middle. Base of epinotum about as long as the declivity, a little 

 longer than broad, concave at middle, margined at sides, the margins 

 angulate. Petiole shorter and much thinner than the postpetiole, the 

 dorsal surface sloping and highest posteriorly; from above, nearly 

 two times as broad as long, widest in front. Postpetiole one and one- 

 half times as broad as the petiole, a little broader than long, with two 

 coarse, rounded longitudinal ridges which are a little higher and 

 thicker behind than in front. First gastric segment with four strong 

 and even longitudinal ridges for its entire length, the surface between 

 these slightly convex. Legs short, the flexor surfaces of the posterior 

 and middle femora strongly expanded a little basal to middle ; tibiae 

 short and very stout, the anterior pair much shorter than the tarsi, in 

 cross section with the sides meeting at angles. 



Subopaque. Finely and densely punctate throughout, with short, 

 recumbent, white hairs moderately abundant on head, gaster and ap- 

 pendages and sparse on thorax. 



Yellowish brown, the posterior part of head darker than the rest. 



Type-locality. — Honduras : Lombardia. 



aotyfes.—Q:^i. No. 24463 U.S.N.M. 



Described from three workers found in rotten wood. 



This, though evidently a true Cyphomyrmex^ is curious in its very 

 short, stubliy legs and the very strong carinae on the gaster. The an- 

 tennal scapes are shorter and much thicker than usual in the genus. 

 C. strigatnr^ Mayr from Brazil has a similarly sculptured gaster. but 



