40 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



apparently all fresh, 10 were males, and T were large nymphs, the 

 aim being to get as many of the earliest ones of the maturing brood 

 as possible without introducing any belated ones of the parent brood. 

 By this method it was hoped to get the succeeding brood, if there 

 was to be one, as soon in the cages as it appeared in the field, and 

 thus establish a minimum time between broods. 



On August 14 this cage was examined, and all leaf hoppers seen 

 were adults. There were no signs of egg scars or of damage. 



On August 30 but few leaf hoppers could be seen, and no egg scars 

 or damage. 



On September 12 the leafhoppers were almost all gone, and no eggs 

 had been laid, either in the cage or field, and dissection showed 

 that the females had no visible eggs in the abdomen up to date. It 

 was thought at this time that the adults would lay eggs in the fall 

 and then die. Accordingly a new lot was started, as shown below. 



Cages 10 and 11 (large lantern globes). — On August 30, 30 leaf- 

 hojDpers were introduced into No. 10, of which 12 were females. In 

 No. 11 one female and several males were introduced. On September 

 12 no Qgg scars could be found in either cage. 



Cages 13 and 11^. (silk scrim with a glass .top). — On September 12, 

 20 leafhoppers, nearly all of which were females, were placed in 

 cage 13. 



On October 20 the field of beets was harvested. The cages were 

 removed and the beets labeled and sent on for examination. Each 

 leaf and stem, and even the parts of the beet itself protruding from 

 the ground, were examined carefully, but no sign of any egg scars 

 could be found on these beets or on those from the previous cages. 

 Many of the leafhoppers were alive at the time the cages were re- 

 moved, and there seems to be no doubt that they must hibernate as 

 adults. . 



SUMMARY OF LIFE HISTORY. 



By the time the beets were thinned the leafhoppers began to appear 

 in the fields and by the middle of June were well distributed. They 

 gradually increased in numbers for some time after this. Egg laying 

 began at Lehi, Utah, late in June and continued until late in August, 

 each female depositing about 80 eggs, the period of deposition ex- 

 tending through several weeks, the greater number of the eggs, how- 

 ever, being deposited in the ten days preceding the middle of July. 

 The nymphs appeared in small numbers by July 10, and were still to 

 be found in small numbers in September. A great majority of them 

 emerged from the eggs the last ten days in July and changed to 

 adults some twenty days later. The first adults appeared from these 

 nymphs the last of July and continued to increase in number through 

 August. The egg stage in the cage experiments was between thirteen 

 and fifteen days; the larval stage between sixteen and twenty-two 

 days. 



