BIOLOGY OF TOBACCO MOTH AXD ITS CONTROL 7 



about 20 minutes, and females rarely mated more than once. The 

 females appeared to remain on or near food suitable for the larvae, 

 but males were circulating rather freely. 



OVIPOSITION 



After the female has been fertilized egg laying may begin in a few 

 hours, and in nearly all cases observed the first eggs were laid within 

 24 hours after mating. Observations showed that the female was 

 somewhat sluggish for the first few days of her life, the time during 

 which most of the eggs were deposited. Females rarely deposited any 

 eggs before mating. In ware- 

 houses the eggs were laid 

 either singly or in small clus- 

 ters and preferably on or near 

 tobacco. They were found on 

 the burlap covering of Turkish 

 tobacco bales, in the cracks of 

 closely fitting staves of hogs- 

 heads, and on the tobacco 

 leaves. When ovipositing on 

 tobacco leaves in the labora- 

 tory the females usually placed 

 their eggs along the midrib 

 and larger veins (fig. 4). Dur- 

 ing the process of egg laying 

 the moths were quiet, with the 

 wings folded horizontally 

 along the body and the legs 

 somewhat apart. The tip of 

 the ovipositor was pressed 

 against the leaf and was be- 

 neath the wings, so it was dif- 

 ficult to observe the actual 

 process of egg laying. Fe- 

 males demonstrated a strong 

 preference for ovipositing in 

 the meshes of burlap or screen 

 wire, particularly the latter. 



The ovipositing moths do not feed but consume small quantities of 

 water. The effect of imbibing water on the rate and number of eggs 

 laid was not determined in these studies. Norris (13, pp. 335-3 J+6 '). 

 however, has recorded a study of the influence of water on the fecund- 

 ity and longevity of moths of the genus Ephestia. The following 

 statements by her are of interest : 



Both the fecundity and longevity of E. elutella females are approximately 

 doubled if the moths are allowed access to water. The actual reduction figure 

 for fecundity of 47 percent is very slightly lower than that obtained in most of 

 the experiments with E. cautella, but the smallness of the number of individuals 

 concerned in this experiment makes it improbable that this is of any significance. 

 Larger numbers of E. elutella were not available at the time of the experiment- - 

 the breeding of this species in captivity presenting considerable difficulty — and it 

 was not thought necessary to repeat it at a later date as the result obtained was 

 so very definite. 



Moths rarely have access to water in tobacco warehouses ; it is likely, 

 however, that the moisture content of the tobacco or air influences the 



Figure 4. — Eggs of the tobacco moth show- 

 ing a characteristic placing of the eggs 

 along the midrib and veins of a tobacco 

 leaf. X 10. 



