422 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
57. Eciton (Labidus) crassicorne F. Smith. 
Common at Cearé-Mirim and at Carnahubinha (near Natal) where 
armies were frequently seen toward evening, either on the ground or 
in the nests of ground-inhabiting ants. 
58. Eciton (Labidus) esenbecki (Westwood). 
A single male of this species was taken at light at Porto VAlho. 
59. Eciton (Labidus) sulcatum (Mayr). 
Several males were taken at light at Independencia. 
60. LEciton (Acamatus) nitens Mayr. 
A rather large colony of this distinct species, was found emerging 
at dusk from beneath our house at Independencia. 
61. Eciton (Acamatus) pilosum F. Smith. 
Taken at Independencia and Paré. Several armies were encoun- 
tered. I collected a number of specimens from a large column which 
was crossing a railroad track at Independencia, whereupon the column 
broke up, but formed again and continued its march, this time beneath 
the rail. A column found in the woods at Para was travelling under- 
ground, except where it crossed a path. Here it emerged and con- 
structed a trail with embankments on each side. 
62. Eciton (Acamatus) legionis F. Smith subsp. crenulatum, 
subsp. nov. 
Plate 1, fig. 1. 
Worker. (Plate 1, fig. 1). Length 3.5 to 5 mm. 
Head, excluding mandibles, longer than broad, with nearly straight 
sides and rounded border; posterior corners angulate. Frontal 
carinae nearly straight. Outer border of antennal pits strongly 
carinate. Anterior margin of clypeus flat, projecting at middle. 
Mandibles stout; the blade edentate. Antennae robust; scape 
extending a third its length beyond the occipital corners, constricted 
