1903.] NATURAL SCIENCES OF PHILADELPHIA. 83 



The advances are made by the male, and there is a distinct court- 

 ship process, which a vigorous male may maintain for two or three 

 hours at a time with few interruptions when the female is recalcitrant. 

 In natural conditions a large number of individuals often occur 

 together on a limited area of ground, such as a moist open spot in a 

 meadow ; here probably the male does not make so prolonged a court- 

 ship, but on finding one female not eager or aggressive he probably 

 seeks another. The males are somewhat smaller than the females 

 and considerably weaker, but they are also quicker, so that they can 

 generally escape from an aggressive female. There is a marked 

 sexual color difference, the male being deep black and the female 

 more brownish. Gravid females are always hostile to males, and 

 once that such a female has made a determined rush at a male he 

 usually ceases to court her, or when he recommences does so hesi- 

 tatingly. The male recognizes a female as such immediately on touch ; 

 whether he recognizes her by sight alone I cannot tell. In courting 

 a fleeing female the male appears to follow her mainly by sight, but 

 even then he does not appear to find her by sight unless she is moving ; 

 often in his excited march for her he will run right past her without 

 seeing her. But when one of his legs touches a part of her, he immedi- 

 ately reacts by quickly moving back a short distance and, after a 

 brief interval, commences his courting motions with great vigor. 

 These motions he will also continue sometimes for a considerable 

 period after the female has been removed from the cage. In a double 

 cage with a transparent glass partition, a male in one compartment 

 and a female in the other, I have not seen a male court a female, 

 though he certainly sees her through the partition; probably, then, it 

 is touch of a female that impels him to courting activity. 



The courtship motions are as follows: The male stands with his 

 body well elevated above the ground (an attitude that a female takes 

 only when she is aggressive) on his three posterior pairs of legs, his 

 head higher than his abdomen, so that the long axis of his body describes 

 an angle of 30°-40° ^\^th the surface of the ground. He waves his palp 

 upward in the air {i.e., straightening them out before his head) and 

 flexes them outward, from one to three times, then draws his body 

 slightly backward and downward, rapidly waving in the air the out- 

 stretched palpi and first pair of legs, and spasmodically shaking the 

 whole body with the violence of the movement. The vehemence 

 and to some extent the attitudes reminds one forcibly of a small 

 terrier barking at a cat. The movement of the palpi exhibits most 

 clearly their relatively huge, black terminal joints. When the male 



