1944] Ammobcenetes from Nevada 149 
sides of the head, thorax, first few abdominal segments, hind 
femur and tibia are marked irregularly with similar color. 
Length of pronotum 2.6 mm.; of hind femur 8.7 mm. 
Allotype: female. Data same as for type. 
Similar to the type except in terminal abdominal structures 
and the following features: the left, front tibia has four ventro- 
cephalic spurs; middle tibiae each with three ventrocephalic 
and no ventrocaudal spurs. Subgenital plate entire, arcuately 
rounded. Ovipositor bulbous at base, rapidly narrowed in its 
proximal third, thence almost parallel. The dorsal margin of 
the upper valve is feebly crenulate in its distal half. The apex 
of the upper valve is upturned (about 30° from horizontal) and 
aciculate. The lower valve is equipped with four, widely spaced, 
slender teeth and a decurved, apical hook. Length of pronotum 
3 mm.; of hind femur 9.5 mm.; of ovipositor 7.2 mm. 
The series includes, besides the type and allotype, twenty 
males and forty-two females, all of which are designated para- 
types. The entire lot was taken at Sand Spring Dune. Among 
the male specimens the minimum pronotal length (four speci- 
mens) is 2.5 mm., the maximum (one specimen) 3 mm. The 
other sixteen specimens all show a pronotal length 2. 6-2. 8 mm. 
The extremes of hind femur length are 8-10 mm., but sixteen 
specimens fall between 8. 5-9. 5 mm. Pronotal extremes among 
the females are 2. 8-3. 6 mm.; thirty-six of the specimens fall 
within the limits 3. 0-3. 5 mm. Similar data for the hind femur 
are: extremes 8.8-11 mm.; with thirty-five specimens within 
the limits 9.5-10.5 mm. For the ovipositor the extremes are 
6. 6-8. 3 mm. All but three specimens fall within the limits 
7.0-8.0 mm. 
The number of ventrocaudal spurs on the front tibia is a 
fairly constant feature, probably generic rather than specific. 
Five specimens show five ventrocaudal spurs on one front tibia, 
one has five spurs on each front tibia while one specimen has 
only three such spurs on one of its front tibiae. The dorsal 
armament of the middle tibiae is also rather constant. Four 
specimens have five spurs in the dorsocephalic series while three 
specimens have five spurs in the dorsocaudal series. None has 
a 5-5 armament and in all cases the aberration is unilateral. It 
is not correlated with sex. 
