248 UNIVERSITY OF COLORADO STUDIES 



of yellow on the legs also varies. In one female there is a small yellow 

 spot on the pleurae. 



Stizus godmani lineatus (Cameron). 



Stizus lineatus Cam., Biol. Centr. Am. (Hym.), Vol. II, p. 108, PL V, fig. 7, a, b. 



The amount of black on the abdomen varies. The amount of yellow 

 on the pleurae varies; in one specimen the pleurae are entirely pale, 

 while in another they are largely black. The pale lines on the mesono- 

 tum vary in strength, in one specimen they are very faint. There is 

 one specimen with the lines on the mesonotum very small, and very 

 dark. Although it has a larger number of characters in common with 

 this variety it resembles very closely godmani godmani. The lines on 

 the mesonotum are very faint, the pleura is mainly black, and the abdo- 

 men is as in godmani godmani. 



Stizus godmani flavus (Cameron). 



Stizus flavus Cam., Biol. Centr. Am. (Hym.), Vol. II, p. 103, PL V, fig. 9, a, b, c. 

 Stizus flavus Fox, Proc. Acad. Nat. Sci. Phil., p. 268, June, 1895. 

 Stizus flavus var. subalpinus CklL, Proc. Dav. Acad. Nat. Sci., Vol. VII, p. 142, 1898. 

 Stizus subalpinus Johnson and Roh., Ent. N., p. 374, October, 1908. 



The black is usually entirely absent in the Boulder specimens. The 

 three basal joints of the flagellum are sometimes yellow. 



The following table may show the relative abundance of the three 

 forms at Boulder. It is made from the specimens which were collected 

 July 31, 1908, at the nesting site spoken of above, by sweeping with a net 

 at random during the warmest part of the day. 



Name Number of Specimens 



2 6 



godmani godmani 8 1 



godmani lineatus 1 3 



godmani flavus o 2 



The finding of these three forms together and in the proportions given 

 above suggests that they are Mendelian, and that godmani flavus is 

 recessive while godmani godmani is dominant. It would be very inter- 

 esting to obtain a large series from the same nest, and see if the different 

 forms do exactly follow the Mendelian ratios. It is the writer's desire 

 to carry on such experiments next season. 



