70 PROCEEDINGS OF THE ACADEMY OF [Jail., 



made a short jump upon her, and quickly got into copulatory attitude, 

 she motionless in his embrace. Their position was as in the case of 

 9 No. 92. Xd^ No. 91; the act lasted from S.o5 to 10.22 P.M., 1 hour 

 and 27 minutes; the palpi were inserted alternately, the right 16 times 

 and the left 15 times. Then he rose, she also started up quickly, 

 chased and killed him within a few seconds, and ate him. 



(4) 9 No. 186 was pregnant when I introduced c5^ No. 91 on June 12, 

 and she killed him. 



In all these cases there was no sign of a courtship on the part of the 

 male; after touching the female, he would raise his fore-legs in defensive 

 attitude, and if she was desirous she would approach him with lowered 

 fore-legs, otherwise she would try to kill him. Now there is a notice- 

 able secondary sexual difference : the tibiae of the first pair of legs of 

 the male only are covered thickly with long, vertically implanted 

 black bristles, making them look like miniature test-tube brushes. 

 When the male stands before the female with these legs flexed, as he 

 does, with the patellse close to the sides of his cephalothorax and his 

 body crouched near the ground, the tibiae are more horizontal than 

 inclined upward. This, then, is not the best attitude to exhibit them 

 to the female; they would be best shown off if they were directed 

 vertically upward. On this account, this bristling of the tibiae can 

 hardly be regarded as a sexual ornament that is exhibited to charm 

 the female. Further, it may be noted that this position of the first 

 pair of legs is also assumed l^y the female when roughly handled or 

 frightened; it is an attitude of defense of the species, not of sexual 

 exhibition. These bristles are possessed only l3y the mature males. 

 I could not determine that they serve any particular purpose, though 

 certainly they give these legs a firmer hold upon the abdomen of the 

 female during copulation. 



Sperm-induction. — cT No. 91, immediately after his copulation with 

 9 No. 92 on June 3, moved to another corner of her cage and spun 

 upon the floor from 10.11 to 10.15. Then as he was interrupted by 

 her approach, I separated her by use of the sliding partition. He 

 commenced spinning again at 10.19, at the angle of a wall and the 

 floor, brushing his spinnerets to and fro upon the glass, on the floor 

 and on the. wall, all the time beating the tips of his palpi upon the 

 overspun area. This continued up to 10.32, when a fine covering of 

 silk, barely visil^le with a hand lens, covered that part of the floor. 

 At_10.32 he elevated his abdomen slightly, still standing over the silken 

 covering, and discharged a minute globule of sperm from his genital 

 orifice upon the silk sheeting. This globule rolled to the ventral 



