Walter Ritchie 327 



about one month's time from the date of laying. These cracks have been 

 suggested as places chosen for egg-laying, the real fact being that the 

 crack is the result of the egg-laying. 



One egg only is inserted into each incision. It is quite a common 

 occurrence, however, to find on badly infested stems, two or more eggs 

 placed close to one another, but careful examination shows that each egg 

 has been forced into a separate incision. 



On several occasions one found females inserting their ovipositors 

 into egg- bites without eggs being laid. It is a common occurrence to find 

 more egg-bites on stems than there are eggs. 



Owing to the position taken up by the female during oviposition, 

 namely, with her body at right angles to the long axis of the stem, the 

 eggs are always placed with their long axis in the horizontal direction 

 (Fig. 22); exceptionally eggs were found slightly tilted. 



The time taken for the egg-laying process is variable. In one case 

 I observed that a female remained in the egg-laying position for five 

 and a half minutes, while on another occasion she remained thirty-two 

 and a half minutes. 



The egg-bites, when newly cut, and into which eggs have been in- 

 serted are very narrow, to the eye appearing as a thin line, and until one 

 gets familiar with their appearance they are very apt to be overlooked. 

 In course of time the bites open or gape, and ultimately show as longi- 

 tudinal dark cracks. In this stage they are very readily detected on 

 the surface of stems. These bites are the only external evidence of the 

 presence of eggs. 



The total number of eggs laid by a single female is variable. The 

 lowest number I ever counted was twenty eight while the highest was 

 fifty-one. All the eggs are not laid on one stem, but spread over several. 

 As a rule the younger the stem chosen the fewer the eggs laid on it. As 

 an illustration, I have counted as many as ten to twelve eggs on several 

 twelve year old stems, while seven was the average number on the 

 five year old ones. 



As will have been noticed in the study of the structure of the repro- 

 ductive organs of an egg-laying female, all the eggs present in the ovaries 

 are not mature at one time, a fact further borne out in the breeding 

 experiments described later. Usually one finds on the dissection of the 

 ovaries of a ripe female that only twenty-four eggs are mature at one 

 time. The time taken to complete egg-laying is variable. In my experi- 

 ments it extended from fourteen days to three weeks. In one particular 

 case of egg-laying kept under close observation, as many as eight eggs 



