1966] 
Evans — Neotropical Pompilidae 
117 
by 1.6 times its own length). From Asthenoctenidia, Aridestus differs 
in having a much shorter and more angulate pronotum as well as 
a complete postnotum which is at least nearly half the length of the 
metanotum. The male terminalia of the three genera show only 
minor differences. 
As noted above, the citation of the type species of Aridestus should 
be corrected to read: Pompilus bergi Holmberg, 1881 (monobasic). 
The following is a redescription of the genus. 
Small wasps, 5-12 mm in length; known species black with ab- 
domen rufous except often fuscous at extreme base and apex (apical 
fourth sometimes fuscous in males) ; males usually with an inter- 
rupted pale yellow band along the posterior margin of the pronotum 
and always with the apical abdominal tergite in large part pale 
yellow or whitish. Mandibles with a single tooth on the inner mar- 
gin; clypeus truncate, its width equal to or slightly less than the 
lower interocular distance; front narrow, middle interocular distance 
not exceeding .58 times transfacial distance; front with a median 
linear impression from the antennal bases to the anterior ocellus; 
vertex passing nearly straight across between tops of eyes. Antennae 
short and in the female slightly incrassate, the flagellar segments 
somewhat flattened on the outer surface; third antennal segment in 
the female 2. 5-3. 5 times as long as thick, .50.65 times upper inter- 
ocular distance; third antennal segment in male shorter than fourth 
segment, 1.4- 1.9 times as long as thick; apical antennal segment of 
male obliquely truncate at tip. Pronotum along midline very much 
shorter than mesoscutum, in the female somewhat bulging antero- 
laterally; posterior margin broadly subangulate or subarcuate; post- 
Figs. 1 and 2. Male genitalia of species of Aridestus , ventral aspect. 
Fig. 1. A. bergi (Holmberg). Fig. 2. A. jaffueli (Herbst). 
