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On the dimorphism of the males of Maevia vittata, 

 a Jumping Spider. 



By 



Theophilus S. Paiuter, Ph. D., 



Yale University, New Haven, Conn., U. S. A. 



Witb 1 Fignre in the tezi 



The Jumping Spider, Maevia vittata, is the only species of 

 Araneiiia which exhibits a distinct dimorphism in the males.') As 

 is well known to Arachnulogists, the males of this species are of 

 two types, one variety being gray much like the female, and the 

 other variety being pitch-black witli three tufts of hairs on the 

 anterior part of the cephalothorax; see Fig. A5 and AI. Tlie first 

 type I have called the "gray variety" and the second, the "tufted 

 variety''. Although it is stated by tlie Peckhams that the gray 

 males never have tufts, in books upon spiders, it is often said that 

 the two types merge into one another. 



The Author has recently completed a study of the spermato- 

 genesis of the two tj'pes of males (article in publication), and 

 several points of diflference were found between them, particularly. 



1) The Peckhams (1889a) raention one other species of Allidae, 

 Zygohallus hctlini, in which the males fall into two classes. One class 

 consists of very large males while the second class is made up of small 

 individuals. From their description , I judge that the males are 

 otherwise alike. 



