THR BEMBECID WASPS OF BOULDER COUNTY 247 



(S. flavus subalpinus Ckll). The finding of these three different forms 

 nesting together in the most friendly manner has led the writer to con- 

 clude that they all belong to the same species. To strengthen this con- 

 clusion no structural characters can be found to separate these widely 

 different color forms. I have examined all my specimens carefully and 

 have also sought for characters in the original descriptions, but without 

 success. I would not, however, reduce these distinct color races to 

 synonymy; on the other hand I would object to such an arrangement, 

 because for one thing I do not consider the fact they nest together proves 

 that they are the same, and again it is an undesirable practice to lump 

 varieties which are easily separable. The finding them all assembled 

 together in this one colony at Boulder does not indicate that they are 

 always found together, and that in different localities they would not be 

 found in different ecological areas. I would call these different forms 

 varieties and separate them as follows: 



Insect mostly black; femora entirely black; mesonotum without yellow 



godmani godmani Cam. 



Insect largely yellow or greenish-yellow; femora partly, usually entirely, yellow; mesono- 

 tum with some yellow 1 



1. Pectus black; mesonotum black with two narrow, longitudinal lines; pleurae usually 

 marked with black; markings usually greenish-yellow . . godmani lineatus Cam. 

 Pectus yellow; mesonotum with three black lines to rest yellow; pleurae without black; 



markings and color bright yellow godmani flavus Cam. 



Stizus godmani godmani (Cameron). 



Stizus godmani Cam., Biol. Centr. Am. (Hym.), PI. U, fig. 8, a, b, c. 



Stizus agilis Cam. (not S. agilis Sm.), ibid., p. 102. 



Stizus godmani Fox, Proc. Nat. Sci. Phil. p. 267, June, 1895. 



Stizus (Stizus) godmani Johnson and Roh., Ent. N., p. 374, October, 1908. 



A number of specimens of this variety collected at Las Cruces, N. M., at 

 flowers of Solidago canadensis by C. H. T. Townsend and given to me by 

 Professor T. D. A. Cockerell vary among themselves in size (the smallest 

 being 7 mm., the largest 10 mm.) and the abundance of yellow markings. 

 The clypeus is entirely black, as are also the metathoracic spines in one 

 of them. The flagellum is entirely black in another. The Boulder 

 specimens are on the average more robust than the New Mexico ones. 

 The abdominal bands are broader; the clypeus is in some specimens 

 entirely yellow while in others it is yellow at the sides only; the amount 



