COLORATION IN POUSTKS. 1 7 



Naturally, from the manner of collecting, the various classes are not 

 to the same degree available for the decision of these questions. First, 

 those collected at random are valuable mainly by comparison with the 

 nest variations, since from them we gain knowledge of the condition 

 of the species for a wider area, but nothing concerning their origin and 

 home relations. Secondly, we must regard the evidence from the 

 specimens captured on the nest with some degree of allowance, since 

 it is highly probable that wasps sometimes lose their way and are not 

 always so certainly driven away from strange nests as has been affirmed 

 for other social Hymenoptera. And, finally, even when the imagines 

 were secured directly on emergence, we can not rely with certainty even 

 on the female parentage of the colony, for in several instances two and 

 even three wasps were observed cooperating in the founding of the 

 nest, although it was not easily determined whether these wasps shared 

 equally in the production of the young. We thus see how complicated 

 the relations here become. It is probable that each female is fertilized 

 by a number of males, whose color markings are necessarily unknown, 

 and if a nest is the work of several wasps, the colony for which it serves 

 as a home is to be regarded as the offspring of a variable and in some 

 cases a comparatively large number of parents. 



In spite, however, of the slight promise in store for such an exam- 

 ination, the distribution of material among the different nests was made 

 out and the result is shown on fig. 9. A particular letter is assigned 

 to the members of each colony, as indicated in the explanation. The 

 distribution of the variously lettered areas thus represents the relation 

 between the variation from the single nest and the range of variation 

 for the whole collection. 



From this it appears that the range of variation for the nests, as 

 a whole, agrees with the range of the random collection. The nest 

 variation material was all collected from the roofs and casements of 

 buildings over an area less than 4 acres in extent, while the random 

 collection was obtained from a region having these buildings as a center 

 and covering an area about 4 miles square. We should expect this 

 consonance if the variation is dependent on slight local differences, for 

 the larger area offers, as far as I am aware, no greater range of habitat 

 than the smaller. The tract is rolling and generally open, well watered, 

 but not low, and in parts heavily wooded. On the other hand, if the 

 trends of divergence depend mainly on the slight difference in color 

 markings of the parents, we may expect the study of nest variation to 

 throw some light on the conditions which govern these variations. 



The first fact that becomes apparent from inspection of fig. 9 is 

 that the colonies differ from one another markedly in their range of 



