32 



COLORATION IN POLISTES. 



Lot I (females) dark ; L,ot i (males) dark ; L,ot 2 (females) light 

 LtOt 2 (males) light. 



Class A, appendages have a large amount of dark pigment, 

 Class B, appendages have a moderate amount of dark pigment. 

 Class C, appendages have a small amount of dark pigment. 

 The distribution of females and males in the classes is as follows : 



Neither of these tables indicates close correlation between the pig- 

 mentation of the body and that of the appendages. The condition of 

 the latter tends to be mediocre, whatever the condition of the bod3^ 

 This is what the examination of any collection of species leads us 

 to expect. The appendages are never conspicuously colored, and 

 usually furnish the least important of the color differences used in the 

 separation of the species. The pattern is always the same as that de- 

 scribed for P. variahis and varies simply in the depth of pigmentation 

 and its spread from the areas indicated. 



The foregoing examination reveals, therefore, a positive correlation 

 between ( i ) the pattern of the dorsal and ventral surfaces of the abdo- 

 men ; (2) the amount of dark pigment in the abdomen and the pat- 

 tern of the clypeus ; (3) the pigmentation of the abdomen and that 

 of the metathorax ; (4) the pigmentation of the body and that of the 

 appendages. These correlations are graphically expressed in figs. 

 12 to 21. The metathorax shares in the tendency toward sexual 

 dimorphism exhibited in the ventral surfaces of the body and the 

 appendages. We thus clearly see that the coloration of Polistes varies 

 as a whole and along certain definite lines. 



Summary. — The color pattern in P. variatus, then, varies according 

 to the varying encroachment on the yellow hypodermal areas of the 

 darkly pigmented zones. In the given collection that variation is 

 continuous for both males and females, but the latter adhere more 

 closely to the typical or modal condition. Again, the types of mark- 

 ing for the members of the individual colony appear to cluster about 

 that possessed by the female founder of the colony, and the kind and 

 extent of their variation from this type of marking is dependent, in a 

 measure at least, on environal conditions. 



