184 THE CANADIAN ENTOMOLOGIST. 



a little the male would immediately back up until the position described 

 was regained, acting as though any other position was painful, or at least 

 uncomfortable. 



I began cautiously to cut away the branches which would prevent my 

 net rim from reaching the ground, intending to lower the bag over the pair 

 so carefully that they would not take alarm and separate, and then to sit 

 quietly by until copulation was finished, or, if necessary, to le.ive them 

 undisturbed overnight. I had succeeded in clearing away the incon- 

 venient branches without frightening the butterflies, and had just laid hold 

 of the net when my plans were suddenly upset by the male, who released 

 the body of the female and flew to a dead twig a few yards away. This 

 happened at 10.40 a.m., exactly ten minutes after I first sighted the pair. 

 It was then an easy matter to capture the insects. Not being confident of 

 the sex of either, I brought both to the laboratory alive, and after noting 

 such differences as appeared on the visible wing surfaces, I put them 

 together in a cage over a growing plant of vaci/lans* On the r3lh one of 

 the butterflies died ; it proved to be the male. About noon on the 15th I 

 examined the plant with a lens without finding any eggs. Shortly before 

 two o'clock I transferred the female to a cage containing twigs of plum 

 (cultivatedj, V. corymbosum, V. vacillatis and V. pennsylvanicum, and on 

 looking over the plant from which she had been removed, I discovered an 

 egg on the outside of one of the opening leaf-buds. I straightway turned 

 my attention to the imprisoned butterfly. 



Oviposition. — Observation began at 1.57 p.m., at which time she was 

 resting quietly on the gauze. Four minutes later she began to walk about 

 nervously, and at 2.05 drop])ed to a spray of vacillans^ and almost 

 immediately oviposited on the outer scale of an unopened bud. A {tw 

 seconds afterward she returned to the gauze, but continued to move about 

 actively as though seeking a way of escape. At 2.07 she again dropped 

 to the plants, this time alighting on a plum leaf, from which she walked up 

 the stem and over the flowers, jumped to an open flower of vacillans, and, 

 with more debberation than before, oviposited on the calyx (2.0S), returning 

 shortly to the gauze. Wishing to determine the minimum interval between 

 the laying of two eggs, I removed two of the four uprights which held the 

 netting in position, and by bringing the butterfly close to the plants I was 



*The weather for the next few days may be of interest, as it possibly 

 influences to some extent the lentflh of time elaiisintf between roftiis and 

 ovipositing-. .Ma\' Sth, ylh anil lotli i-oUl, chmdy, with rain al inler\als; iilh fail" 

 but cold ; 12II1 hazy, with keen wind, rain in alU'riioon ; i.^tii cold, rain ; i.jtli 

 fair and warm ; 15111 fair and warm. 



