1902.] NATURAL SCIENCES OF PHILADELPHIA. 63 



which is not reflexed ; wiugs fusco-hyaliue, darkest anteriorly. 

 Length 6 mm. 



Var. a. — Head, except the usual yellow marks, and a black spot 

 including ocelli, rufous ; only segments 1 and 2 yellow at apex. 



Var. h. — Rufous color absent on the parts indicated in the de- 

 scription except the tegulse; clypeus except base, and antennae 

 above, black ; border of concavity of middle segment, and mandi- 

 bles more or less, yellow. 



Corumba (April). Three specimens. 

 Odynerus relativus n. sp. 



?. — A closely allied species to 0. rtifosuffusus ; in coloration it 

 differs by the absence of rufous from the pronotum, etc. , and the yel- 

 low marks are more extended ; clypeus yellow basally, otherwise light 

 rufous or black ; frontal line united with spot at base of antennae ; 

 a broad yellow line traversing the pronotum ; mandibles in greater 

 part, a variable spot under tegulae, margin of concavity of middle 

 segment, and segments 1-5 distinctly at apex, yellow ; hind margin 

 of pronotum yelloAV -testaceous ; punctuation coarser perhaps than 

 in rufosuffusus and on the thorax the punctures are larger, shallower 

 and more separated ; clypeus with a rather broad triangular emar- 

 gination ; orbit of the eye in the emargination not margined by 

 fovese; pronotum acutely dentate, the crista curving backward 

 much more than in rufosuffasus ; a single large tubercle between 

 hind ocelli. Length 7 mm. 



Corumba (April). One example. 

 Odynerus praecox Sauss. 



Eight females, and a large series of males. Chapada (April^ 

 September to November); Corumba and Pedra Branca in April; 

 Santarem. The banding of the dorsal segments beyond the second 

 may be present or absent, and the flagellum beneath varies from en- 

 tirely black to rufous. Odynerus zonatus Sauss. is probably a 

 variety of prcecox. 

 Odynerus nasidens Latr. 



One specimen (?). Chapada (September). 

 Odynerus brevithorax Sauss. 



A female specimen from Chapada (April). 

 Odynerus (Odynerus) corumbae n. sp. 



^. — Black; rather densely sericeous witli pale brownisli pile, the 

 pubescence of front pale; scape and i)edicelluiii Ix'ueatli, and teeth • 



