THE MARGUERITE FLY. 33 



cheeseclotb bags was from two to five days, although a single individual 

 lived seven days. On the other hand, males confined with females under 

 the same conditions lived from four to thirty days, the greater muriber 

 hving coDsiderablj' longer than five days. 



To determine whether this longer period of life was due to feeding or to 

 possible psychological influence or physiological effects following mating, 

 males were isolated upon leaves upon which females had previously been 

 confined and which leaves had been pierced by them. The males were 

 thus afforded an opportunity to feed without being subjected at the same 

 time to possible influences above mentioned, due to the presence of the 

 females. Again, in order that they might have a condition approximating 

 to that when free and at large upon the plants in the greenhouse — leaves 

 ■with both old and new s^^abs — each series of males and females was 

 alternated between the leaves, upon which they were respectively isolated 

 at frequent intervals. Of the 19 males kept under these conditions only 

 3 lived considerably longer (eleven, twelve and tliirteen days, respectively) 

 than those kept by themselves on the unpunctured leaves. 



On the other hand, of the 43 males confined with females of various ages 

 in glass jars in absence of all food, the females being replaced daily or 

 every other day, and mating observed in many instances, the usual lon- 

 gevity (if a single individual which lived four days is excepted) was three 

 days. 



Oviposition. 



The details of the egg-laying process are practically a repetition of those 

 of the feeding process. It differs from the latter process only in one 

 essential particular, viz., the deposition of a single egg in the horizontal 

 incision, in immediate contact with the epidermis of the leaf, just before 

 the ovipositor is withdrawn. The tissue in contact with the epidermis 

 having been sufficiently cut or macerated, the ovipositor is partially 

 retracted for a few seconds, then protruded for a final and last time (often 

 twice), the egg being deposited at the same time. The time spent in 

 piercing and cutting the tissue in oviposition, in the instances observed by 

 the writer, varied from twenty to forty-five seconds, and the subsequent 

 feeding, from five to thirty-eight seconds. Only in a single instance did 

 a female fail to feed after the deposition of the egg. The eggs are, as a 

 rule, deposited from the lower surface of the leaf, and can be seen through 

 the epidermis with the aid of a hand lens when the fight is favorable. As a 

 rule, the young leaves at the apex of a branch, or shoot, are not oviposited 

 in, although they may be pierced for feeding purposes. The latter part 

 of the afternoon appears to be a favorite time for oviposition. 



Dr. Britton (Eleventh Report of the State Entomologist of Connecticut, 

 1911, p. 342) states that "the eggs are laid in or on the underside of the 

 leaves." The writer has found only one egg deposited on the surface 

 (lower surface) of the leaf during his investigations, and he regards the 

 phenomenon as abnormal, as the larva, as will be seen below, is unable to 



