THE AERIAL WEB SPINNERS 191 



twigs and the leaves. Hanging to the lines, or hidden among the 

 near-by leaves, may be one or more egg sacs, beautifully and dur- 

 ably made and featuring a long, coarse stem drawn of! from the 

 globular base. During the daylight hours Mastophora clings to a 

 twig or leaf, completely immobile, perhaps deriving some protec- 

 tion from her resemblance to various inanimate objects. Even 

 when handled, she shows only a momentary evidence of life, and 

 may be rolled around in cupped hands like a marble. Few spiders 

 are so completely inscrutable. 



But Mastophora is a creature of the evening and night, and as 

 one watches her then in the performance of her marvelous routine, 

 one forgives the earlier listlessness. The disappearance of the last 

 rays of twilight is the signal for action; she takes up her position 

 for the evening's sport. 



With plump body swinging from the ends of her legs, she moves 

 to one end of a branch and affixes her thread to the lower side by 

 pressing her spinnerets against the bark. Grasping this thread with 

 one of her hind legs and holding it away from the branch, she 

 crawls several inches farther along and pastes the other end firmly 

 in place. The result is a loosely hung line, which she often strength- 

 ens with an additional dragline thread. This strong trapeze is hung 

 far enough below the branch to allow a clear space for casting. 



Moving to the center of the line, Mastophora now touches her 

 spinnerets and pulls out, to a length of about two inches, a new 

 thread that lies clear of the other. Keeping it attached to her spin- 

 nerets and held taut, she combs out upon it quantities of viscid 

 silk. Each hind leg alternates in producing the liquid, until a shin- 

 ing globule as large as a small bead is formed. 



The spider now pulls this line out still farther, allowing the 

 weighted portion to drop part of the distance to its natural point of 

 equilibrium, then she turns and severs it just below the globule with 

 the claws of one of her hind legs. The freed line swings back and 

 forth like a pendulum, but the spider turns quickly and approaches 

 it, searching and groping with her front legs until she is able to 

 grasp it. Quickly she swings her massive body and seizes the trapeze 

 line by the hind legs of one side, adjusting the casting line between 

 her palpi and one of her long front legs. Poised and ready now is 

 the boleadora, waiting with the patience that characterizes her 

 for the approach of a suitable victim. (See Text Fig. 5, C.) 



Also aroused to activity at this time are many nocturnal insects, 

 which soon fly along accustomed lanes, dipping down close to the 

 foliage and fluttering in and out among the branches. A large- 



