MANN: THE ANTS OF BRAZIL. 435 
deeply concave; on either side with a high ridge which terminates in 
an acute, erect spine, about two thirds as long as the base. Petiole 
twice the length of postpetiole, the node broader than long, with 
conical sides; seen from the side concave in front, higher than post- 
petiole. Postpetiole broader than long, the sides conical. 
Gaster smaller than the head. Legs slender. Head and gaster 
shining, thorax and petiole subopaque. Mandibles very finely punc- 
tate. Head densely, minutely punctate. Thorax, petiole, and post- 
petiole with more dense punctures. Legs finely punctate, shining. 
Thorax without hairs, head, petiole, and gaster with sparse, 
scattered erect hairs. 
Color pale brownish yellow, mandibles dark ferruginous. 
Worker. Length 2 mm. 
Head, excluding the mandibles, a little longer Lier broad, with 
convex sides and evenly rounded posterior margin. Eyes at sides of 
head in front of middle. Mandibles with two very acute teeth. 
Antennal scapes extending one third their length beyond the occipital 
margin. Thorax similar to that of the soldier, but the prothorax 
more rounded at sides. Epinotum, petiole, and postpetiole similar 
to those of soldier. Gaster as large as head. 
Head, legs, and gaster shining, the rest of the body opaque. 
Pilosity and color like those of the soldier. The hairs are even 
sparser. Mandibles and border of clypeus darker. 
Described from several soldiers and workers from Madeira-Mamoré 
R. R. Camp 37. 
’ Differing from the typical form in the smaller size, and pale color. 
The antennal scapes of the soldier are proportionally longer, reaching 
three fourths the distance to corners of occiput. 
Named after Dr. James Laidlow, of the medical corps of the Madeira- 
Mamoré Railroad. 
84. Pheidole (Pheidole) biconstricta Mayr. 
Manaos, Porto Velho, Abundé and Camps 39, 41, 43 Madeira- 
Mamoré R. R. 
On the Rio Madeira this species was very common, nesting in or 
beneath rotten logs. The colonies are very populous. 
85. Pheidole (Pheidole) biconstricta subsp. bicolor Emery. 
Madeira-Mamoré R. R. Camp 39. 
