300 Annals Entomological Society of America [Vol. V, 
covering the cavity which holds the folded sucking mouth 
parts. With the large mandibles closed over it the labrum is 
not accessible for study except by dissection. There has 
therefore been no attempt made to use its characters for classi- 
fication. 
Mandibles. Each mandible is a fairly long and strong hook 
decidedly suggesting rapacious habits. The front surface has 
a deep longitudinal furrow at its inner border while the hind 
surface is set with stiff outstanding bristles, extending from a 
deep furrow at its outer border. Between these two and on the 
front surface is a third shallow furrow which runs the whole 
length of the mandible. A study of many individuals shows a 
variation in the structure and relative proportions of the man- 
dibles, they probably being worn and modified by the digging 
habits of this*group.. Im the female the middle of themnuner 
margin sometimes shows tiny blunt projections (hardly long 
enough to be called teeth) varying in size with the different 
species and in the same individual. The male mandible is 
more delicate than the female. Its inner middle margin shows 
three well defined teeth besides the sharp end tooth. The 
surface of the mandibles is smooth and shining. 
The maxillary palpus 1s composed of six segments and the 
labial palpus has three segments. 
The other mouth parts cannot be studied except after 
dissection and therefore are not readily available for analytical 
work. For this reason they are not considered here. 
Antenne. In the male these are long, almost cylindrical 
and almost straight. The basal portion of the first segment or 
scape is a small spherical bulb which has every appearance of 
being a separate segment. This is not the general opinion 
however so it is here considered a part of the scape. The distal 
portion of the segment is long and very near a perfect cylinder. 
It narrows quickly at either end to articulate with the bulb 
and the pedicle. The pedicle is small and cup-shaped, its 
smaller end toward the body. These segments are smooth 
and shining. The filament consists of eleven cylindrical 
segments, very little thickened in the middle and only separated 
from each other by a fine seam. Asa whole it is stout gradually 
increasing in diameter to near its end, then gradually reducing. 
The segments of the filament are considerably longer than their 
diameter and are dull, not reflecting the light. 
