254 PROCEEDINGS OF THE ACADEMY OF [1897. 



joints of flagellum equal in length ; pronotuni rounded behind ; 

 scutellurn prominent but not unusually so; middle segment rather 

 flat, impressed for two-thirds its length, the posterior surface, which 

 is but feebly defined, depressed ; legs tolerably spinose, claws bifid, 

 longer spur of hind tibiae not equal to two-thirds length of first hind 

 tarsal joint ; abdomen subpetiolate, compressed, clavate, first segment 

 longer than second ; wings subhyaline, a fuscous cloud fills base of 

 marginal, apex of second and third submargiual entirely, a trace of 

 a fascia crosses the superiors at apex of median cell, second submar- 

 ginal rhomboidal, much higher than broad, the third submarginal 

 much the larger, narrowed .somewhat more than half to the mar- 

 ginal. Length 12 mm. 



Chapada (April). One specimen. 



Pompilus serratus n.sp. 



$ . — Black, with silvery-sericeous pile, especially on the thorax 

 beneath ; flagellum beneath fulvous; spot on scape beneath, on each 

 side of clypeus, mandibles except apex, hind margin of pronotum 

 obscurely, anterior coxae in part, calcaria of four hind legs, base of 

 second abdominal segment and spot on seventh dorsal segment, 

 white; palpi, anterior tibiae and tarsi, and tegulae, testaceous; ante- 

 rior margin of clypeus slightly incurved or subtruncate ; front not 

 impressed ; eyes reaching mandibles, inner orbits sinuous, somewhat 

 diverging above, the space between them at the vertex about equal 

 to the length of antennal joints 4 and 5; space between hind ocelli 

 barely half that between them and eyes ; joints of flagellum thickest 

 at base, thereby giving the flagellum a serrated appearance, the first 

 joint longer than the second ; pronotum angulate behind ; middle- 

 segment not impressed, sloping gradually from base to apex ; legs 

 not strongly spinose, claws of anterior and middle tarsi bifid, of the 

 hind tarsi apparently simple, longer spur of hiud tibiae equal to more 

 than two-thirds the length of first hind tarsal joint ; abdomen com- 

 pressed, subpetiolate ; wings subhyaline, iridescent, changing into a 

 beautiful milky-blue color when the insect is held in certain lights, 

 a fuscous cloud includes part of marginal and second submargiual, 

 and third submarginal entirely, and along the basal vein is a fuscous 

 stain ; second submarginal rhomboidal, higher than broad, smaller 

 than the third, the latter narrowed nearly two-thirds toward margi- 

 nal. Length 11 mm. 



Chapada (April) ; Santarem. The antennae are partly missing in 

 both specimens. 



