28 



COLORATION IN POLISTES. 



CORREI^ATION OF SIZE OF ABDOMINAL SPOT WITH MARKINGS OF METATHORAX. 



Under this head we will make out, first, the correlation between the 

 abdomen and the condition of the lateral stripe of the metathorax, and, 

 secondly, the relation between the former and the condition of the 

 median stripes. The metathorax shows variability in the extent of 

 both of these stripes. 



P'iG. 14.— Correlation between character of abdomen and width of median stripes of metathorax, 

 Lot I, continuous lines, loo dark individuals. Lot 2, dotted line, 100 light individuals 

 Width of stripes : a, 0.6-0.9 m™- ; ^> 0.3-0.6 mm. ; c, 0.0-0.3 mm. The dark individuals 

 tend to fall into the class with narrow stripes ; the light individuals into that with 

 broad stripes. 



Fig. 15 —Correlation between dorsal surface of abdomen and size of lateral stripe of metathorax. 

 Lots same as in foregoing determinations, a, lateral stripe about same size as 

 median stripe ; b, lateral stripe reduced to about one-half its maximal length ; c, 

 lateral stripe absent. 



Lots I and 2 correspond with the lots in the foregoing determinations. 

 With regard to the presence or absence of lateral stripe of metathorax, 

 we fix on three classes: 



Class A, lateral stripe absent. 



Class B, lateral stripe shortened to about half its maximal length. 



Class C, lateral stripe present and about the same size as the median 

 stripe. 



