COLORATION IN POLISTES. 27 



The distribution of specimens in foregoing classes is shown as follows: 



In only one case were the borders in both confluent with the lateral 

 spot. In L/ot 2, Class B, 21 specimens had the yellow or brown of the 

 lateral spot confluent with the border, while in Class C this condition 

 was represented in 63 of the specimens. There is thus marked positive 

 correlation between the size of the lateral spot and the width of the 

 terminal border (fig. 16). 



CORRELATION BETWEEN SIZE OF SECOND ABDOMINAL, SPOT AND MARKINGS OF 



CLYPEUS. 



L/ots i and 2 were selected as before, and each lot separated into three 

 classes with respect to the condition of the clypeus. 



Class A, clypeus possessing a broad black spot which extends half or 

 all the way to the ventral border. 



Class B, black area extends less than half way to ventral border, and 

 may be surrounded by a ferruginous margin. 



Class C, black restricted to a mere dot or entirely absent. There is 

 always some light reddish brown present on the yellow background, 

 which may vary from two or three slight dots near the center to an area 

 coinciding with the black area of Class A. 



The distribution of specimens in the above-described classes is shown 

 as follows : 



Furthermore, the blackest of L/ot i contain more pigment than the 

 blackest of Lot 2, and the lightest of Lot 2, Class C, are very much 

 lighter than those of the corresponding class in Lot i . Thus there is 

 found to exist a comparatively close positive correlation between the 

 amount of yellow in the second abdominal segment and that in the 

 clypeus (fig. 17). 



