402 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lie 



Abdomen with broad bands more or less emarginate with black on 

 anterior center, margins with some amber; venter largely yellow with 

 limited amber; pygidium broad basally, tapering gradually to a 

 narrow rounded end apically. 



Male. — Length 10 mm. Black to amber with yeUow markings; 

 close and moderately deep pits; clothed with short silvery hairs. 



Head one-sixth wider than the thorax; face yellow below antennae 

 except clypeal margin, which is dark amber; clypeal border slightly 

 extended from the middle lobe with three very indistinct denticle-like 

 extensions; clypeal surface slightly convex; mandibles without 

 denticles; antennae normal in form except for a slight curvature of 

 the apical segment. 



Thorax black to amber with yellow markings; divided yellow band 

 on the pronotum; scutellum black or with light spots; metanotum 

 yellow or with a broken yellow band; tegulae not elevated, relatively 

 smooth, yellow; enclosure smooth except for minute pits and a few 

 large pits in the lateral angles; mesosternal tubercles absent; pro- 

 podeum black to reddish amber; legs black to light amber to the apical 

 end of the femora, largely yellow beyond; wings subhyaline, clouded 

 along anterior border and apex. 



Abdomen black with broad bands on terga 2 to 6, more or less 

 emarginate on terga 3 to 6; tergvmi 1 black becoming reddish amber 

 on some specimens; anterior half of tergum 2 becoming reddish on 

 some specimens; venter black to more or less infused mth amber and 

 yellow; pygidium with sides subparallel and the apical end rounded. 



Variation. — C. calvfornica Cresson varies in color from the black 

 and yellow form of the Northwest and the Rocky Mountains, repre- 

 sented by the type of the species, to the extremely light forms 

 represented by C. arno Banks. In these lightest forms, the black has 

 been replaced completely by very light amber to yellow. The latter 

 are found mostly in the southwestern desert areas of California and 

 Arizona. It is no doubt largely due to this extreme variation in 

 color that so many species have been erected by former workers who 

 have seen relatively few specimens representing limited areas. It is 

 a matter of opinion which of them, if any, should be considered sub- 

 species. The present author herein has designated the extreme 

 lighter forms, which are more limited in thek distribution, as the sub- 

 species C. calvfornica arno Banks. Cerceris calvfornica Cresson may 

 be confused with related species found in the same area such as C. 

 completa Banks and C. grandis Banks. These are best separated by 

 the characters given in the key. 



Types. — The type male of C. calijornica Cresson, from California 

 is at the Philadelphia Academy of Natural Sciences, no. 1953. The 

 type male of C. jerruginior Viereck and CockereU, from Deming, 



