COLORATION IN POLISTKS. I9 



istics : Thej' nearly all fall into the xanthic classes — that is, they pos- 

 sess conspicuous borders and yellow metameric spots, which may or 

 may not be tinged at the edges with ferruginous. Of these 48 wasps 34 

 are females and 14 are males. The former arise from the fertilized egg 

 and should therefore represent the characters of both parents, and if 

 the male parent differed in any case, we might expect a corresponding 

 variation in the progeny. The latter develop from the unfertilized 

 egg and might therefore be expected to. adhere more closely to the 

 color characters of the female. In point of fact, as regards the most 

 prominentl)' variable characters — i. e., the presence or absence of ferru- 

 ginous on the edges of the metameric spot — the two sexes share alike 

 in these differences. Of the 34 females and workers and 14 males, 

 17 of the former class and 8 of the latter have the ferruginous of the 

 metameric spot absent, or so slight as to be unnoticeable, while 17 of 

 the former class and 6 of the latter have the ferruginous conspicuously 

 present. Not one of the wasps was markedly melanic. In one speci- 

 men only was the yellow materially reduced, in several others almost 

 obliterated by the centripetal spread of the ferruginous margin. This 

 colony accordingly shows, on the whole, rather close adherence to the 

 color characteristics of the female parent, and this adherence is shared 

 equally by males and females. 



The two wasps that were associated in the founding of nest a were very 

 similar in size and general appearance. Both possessed an L-shaped 

 yellow mark in the first abdominal segment, a large brown spot on the 

 second, nothing on the third and fourth, and a small yellow dot on 

 the fifth segment. In one the brown spot of the second segment had a 

 slight yellow dot near its center. We find the individuals in this colony 

 varying from the extremely xanthic to the extremely melanic type 

 along the several lines of divergence. The mode lies distinctly in the 

 melanic type, characterized by the possession of brown spot, or its 

 obscuration by black. The number of specimens falling here is 2 . 5 times 

 that of all other classes put together. Here again we have compara- 

 tively close resemblance to the type of the female parent, but the re- 

 semblance is less marked than in nest/. 



In the construction of nest d, also, two wasps were observed to be 

 associated. One possessed the following markings with reference to the 

 abdomen : Strongly sericeous black segments with borders interrupted 

 in median, dorsal, and ventral Hue ; first segment with a yellow lateral 

 dot, second with large quadrilateral yellow blotch, third and fourth 

 with merest indication of lateral dot, fifth with spot elongated in the 

 direction of the border ; metameric spots on the ventral side of the 

 abdomen entirely lacking. The other showed the same characters, 



