3H S. J. HOLMES. 



female during the efforts of the male to clasp her around the 

 base of the abdomen usually lies quiet with the appendages 

 drawn close to the body. She may be seized by the legs, tip 

 of the abdomen, or any other part of the body, but the male 

 works around until he gets into his normal position which he 

 sometimes attains only after much labor. Females vary greatly 

 however in respect to their willingness to be clasped by the male, 

 certain individuals resisting seizure for a long time. 



So far as could be detected the males do not seek or follow 

 the females at a distance as Parker concluded they did in Labido- 

 cera. The association of the sexes seems to be due merely to 

 chance collisions. Males often attempt to seize other copepods 

 with which they collide regardless of their sex. The males resist 

 such attempts at seizure and dart quickly away, while the females 

 often stop and submit readily to the clasping propensities of their 

 companions. Several males were injured so that they could not 

 resist seizure, and in many cases they were seized by other males 

 who worked industriously until they got their burden clasped 

 around the base of the abdomen in the usual way. These asso- 

 ciations did not last long however ; the active males apparently 

 appreciating that something was wrong soon swam away. Re- 

 cently killed females were often seized and in some cases carried 

 about for a while, but they were finally dropped. Males seem 

 rather more prone to seize dead females than members of their 

 own sex. In one case I saw three males tugging away at a 

 dead female, and they were soon joined by a fourth male who 

 participated in the same effort. 



It is possible that the odor of the female determines to a cer- 

 tain extent the sexual behavior of the males, but my experiments 

 yielded no evidence of this. Several females were put into a 

 tube one end of which was covered with fine gauze and the tube 

 was then placed obliquely in water in which were numerous 

 males. The males showed no tendency to congregate around 

 the end of the tube where the females were confined. In another 

 experiment several females were placed in a glass tube in which 

 a small plug of loose cotton was inserted a short distance from 

 one end. This end was laid obliquely in the water. The males 

 showed no tendency to enter the open mouth of the tube as they 



