108 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



male and female exceeds the combined length of the third and fourth. 

 The mandibles on both male and female are remarkably straight, 

 scarcely curved at the tip, more slender than usual and almost devoid 

 of teeth on the inner border. The reduction of the teeth on the female 

 is very unusual; only one is present and that is vestigial. The 

 pubescence on the head and base of clypeus is long and rather dense ; 

 elsewhere on the body it is sparse and quite short. The wings are 

 hyahne and veins brown. The markings on the dorsum of the thorax 

 and median segment in both sexes are variable; at one extreme we 

 find only short lateral lines on scutum, small lateral spots on scutel- 

 lum and the lateral angles marked with yellow; at the other, broad 

 lateral lines and U-shaped mark on scutum and broad fasciae on 

 scutellum, metanotum and median segment. 



Habitat. — Lower California, California, New Mexico, and Arizona. 



Number of specimens examined — Males, 7; females, 14. 



BEMBIX TROGLODYTES HandUrsch. 



Figs. 177, 178, 202. 



Bembex troglodytes Handlirsch, Sitz. Akad. Wissensch. Wien, Math.-Nat. CL, 

 vol. 102, 1893, p. 829, pi. 2, fig. 29, male, female. 



Male. — Black: Labrum, mandibles except apices, clypeus, lower 

 part of frons, scape except stripe above, spot in front of anterior 

 ocellus, lateral rounded spot on either side of this one, broad anterior 

 orbits, posterior orbits, prothorax almost entirely, tegulae, lateral 

 lines and pair of short discal lines on scutum, lateral spots more or 

 less approximated medially on scutellum, fascia on metanotum, 

 curved fascia on dorsum of median segment usually interrupted 

 medially on the posterior surface of the segment, lateral angles and 

 sides of the segment, metapleurae, large irregular anterior spot and 

 small posterior one on mesopleurae, broad fasciae on tergites 1-6, 

 first narrowly interrupted medially, remainder continuous, second 

 inclosing pair of rounded dorsal spots, third with a similar pair of 

 spots that are usually connected to the anterior black margin, fourth 

 with a pair of anterior emarginations instead of spots, fifth and sixth 

 shghtly sinuate, apex of ultimate tergite, apical border of first 

 stemite, broad apical fascia on second, sometimes inclosing a pair of 

 black spots, lateral spots on 3-5 which may be connected by broad 

 apical bands, narrow ones or not at all, sometimes pair of small 

 lateral spots on 6, spot on coxae, trochanters more or less, femora 

 except more or less basally and stripe below on anterior pair, tibiae 

 except sometimes small spot below on anterior pair, and tarsi, lemon 

 yellow. 



The flagellum is neither spinose nor dentate; segments 4-11 bear 

 specialized areas on their posterior surface, but these do not assume 

 the form of pits or excavations. The middle femora are smooth 



