COLORATION IN POLISTES. 9 



versity ; Prof. S. A. Forbes, University of Illinois ; Dr. George W. 

 Peckham and Mr. C. E. Brown, Milwaukee, Wis. ; Mr. O. S. West- 

 cott, North Division High School, Chicago ; Mr. Lawrence Bruner, 

 Lincoln, Nebr. ; Prof. T. D. A. Cockerell, Boulder, Colo.; Mr. E. S. G. 

 Titus, Fort Collins, Colo. ; Mr. Charles Robertson, Carlinsville, 111. ; 

 Dr. R. E. Kunze, Phoenix, Ariz. ; Mr. Hugo Kalil, Lawrence, Kans. 



GENERAL ACCOUNT. 



Polistes is the name of a genus of wasps belonging to the family 

 Vespida^. They are social in habit, each colony possessing three forms 

 of individuals — males, females, and workers. They construct nests of 

 gray paper from the fibers of weatherworn wood ; these, in the case of 

 Polistes, consist of a simple plate of cells and are never surrounded by 

 any external covering. Each colony is founded in the spring, usually 

 by a single female, commonly called the queen, which, with several other 

 fertilized females, represents the sole survivors of some colony of the 

 previous year. The colony is usually to be considered, therefore, as 

 the offspring of a single mother, but from what is known of the mating 

 habits of the species, it probably represents the offspring of a variable 

 number of males. 



The species is polymorphic. In the case of the females and workers 

 this polymorphism consists simply in differences of size and degree of 

 fertility. According to Von Siebold (26),* the young workers become 

 fertile in the event of the death of the queen and produce eggs which 

 develop parthenogenetically into males, and Marchal has shown that 

 all degrees of fertihty may exist between the absolutely sterile workers 

 and the fertile female or queen. In secondary sexual characters the 

 males differ from the females in the possession of an additional segment 

 in the abdomen, and in the antennae, which are curled at the ends in- 

 stead of being clubshaped, as is the case in the females. They also 

 have bright j^ellow faces and a greater amount of yellow on the ventral 

 surface of the body. 



The genus is almost universal in its distribution, and the species in- 

 tergrade very largely, so that there is serious doubt as to how many of 

 these are valid. Cresson, in his ' ' Synopsis of Hymenoptera of Ameries, 

 North of Mexico," expresses the opinion of many of the systematists 

 who have had anything to do with the genus, when he says : 



Our species of this family (Vespidse) are in much confusion and require a thor- 

 ough revision. The Polistes are exceeding!}- variable and there is no doubt that a 

 careful study of a large collection of specimens will result in a marked reduction 

 in the number of species. 



*The figures refer to the bibliography, p. 87. 



