514 Theophilus s. Painter, 



Spermatogenesis of Maevia vittata. 



General Information. 



Maevia vittata is a rather small gray jumping sjiider found 

 commonly over the greater part of the United States, but curiously 

 localized in its distribution. It is very active and is best caught by 

 "sweeping" grass and low bushes with a fine-meshed net. As the 

 males of this species show a marked dimorphism in form, it seems 

 worth while to describe, in some detail, the types of individuals 

 which one may catch. 



The females are about 8 mm long and are of a general gray 

 color with distinct dark-brown bands on the abdomen. This dark 

 brown may merge into a red on the céphalothorax. 



The males are of two kinds, and, as is usual among spiders, they 

 are considerably smaller than the females. One type is much like 

 the female before she becomes mature; the general color is gray, 

 but the bands on the abdomen are broken up into rows of spots 

 with middle angular markings. Such a male, when fully mature, 

 is somewhat darker than the female and the spots on the legs are 

 more distinct. In the present paper this type of male has been 

 called the "gray variety". 



There is a second type of male which differs quite strikingly 

 from the gray variety. It is pitch-black in color with bright yellow 

 legs, and on the anterior dorsal surface of the céphalothorax tliere 

 are three tufts of hairs projecting forward. This has been called 

 the "tufted variety". 



This dimorphism of the males of Maevia vittata has been known 

 for a long time by arachnologists, but no work has ever been done 

 to determine the ratio in which these two types occur in nature, 

 nor is anything known of the ratio of males to females.^) 



In working out the spermatogenesis of Maevia vittata^ two 

 objects were kept in view. First, I wished to determine the sequence 

 of changes going on in tlie germ cells of tliis jumping spider, and 

 second, it seemed worthwhile to determine if there was any cyto- 



1) Since the present work has been in the hands of the publisher, 

 the author has Htudied these, two questions. The females were found to 

 be as numerous as the males. And the two types of males were equally 

 numerous. See "On the dimorphism of Maevia vittata, a jumping spider", 

 in: Zool. Jahrb., Vol. 35, Syst. 



