MANN: THE ANTS OF BRAZIL. 403 



The following table may help in separating the South American 

 species of Platythyrea. 



A. Mandibles dentate. 



Length 8 mm. (Surinam) sinnata Roger. 



AA. Mandibles without teeth. 



a. Eyes as long as their distance from anterior border of 

 head; petiole strongly bisinuate, the middle portion pro- 

 longed into a short beak. Length 7.5 mm. (Venezuela, 



Brazil) meinerti Forel. 



aa. Eyes smaller, petiole feebly sinuate. 



b. Petiole from above more than twice as long as broad, 

 as long as first segment of gaster ; femora swollen. Length 

 6.7 to 7.7 mm. (Trinidad, Brazil) angusta Forel. 



bb. Petiole from above less than twice as long as broad, 

 femora normal. 



c. Punctures on epinotum very coarse, dilatation of frontal 

 lobes more marked. Length 8 mm. (Venezuela, Brazil). 



incerta Emery. 



cc. Punctures on epinotum finer, dilatation of frontal 



lobes less marked. Length 6 to 7 mm. (Antilles, Central 



and South America) 'punctata Smith. 



6. Typhlomyrmex rogenhoferi Mayr. 

 One small colony, taken from a rotten log at Para, y . 



7. Rhopalopone relida, sp. nov. 

 Plate 1, fig. 4, 5. 



Worker. (Plate 1, figs. 4, 5). Length 2.5 mm. 



Head, excluding mandibles, distinctly longer than broad, broadest 

 behind eyes, the width at occiput about equal to that at base of cly- 

 peus; sides slightly rounded, posterior border feebly concave. Man- 

 dibles long, rather slender, the blade minutely dentate; outer border 

 arcuate at middle. Clypeus subtriangular, broadly rounded at ante- 

 rior border, flattened in the middle. Frontal carinae very short, their 

 basal lobes rounded. Antennae robust; scapes arcuate, extending 

 barely to the occipital corners ; first funicular joint as long as the two 

 succeeding joints together; joints 3 to 9 broader than long; apical 



