LEAFHOPPERS OF THE SUGAR BEET. 39 



Cages 4 (ind 5 (glass globes upon beets about 8 inches in diam- 

 eter). — On Jul}^ 10, IG adult leafhoppers, 12 of Avhich were females, 

 were introduced into cage 4. Previous dissections had shown that all 

 females were bearing eggs, and the presence of a very few small 

 nvmphs in the jfield proved that the earliest ones began depositing 

 eggs some time before. It was therefore expected that some of the 

 females introduced Avould begin depositing at once. 



On July 23 these cages were examined, and in the one containing 

 the leafhoppers the stems were found to be fairly covered Avith ogg 

 scars. Two of the stems were removed and preserved, and found to 

 contain IGl eggs — not more than one-sixth of the total number pres- 

 ent. A number of females were seen in the cage, but no nymphs. 



July 27 the stems showed still more Qgg scars, and there was quite 

 a number of small nymphs that had apparently been out several 

 days. The insects had been in the cage only seventeen days, so these 

 eggs must have hatched within thirteen to fifteen days from the time 

 of laying, under the conditions found in the cage. Another stem 

 Avas removed and preserved, and the rest left as before. 



On August 3 another stem was removed. The eggs had almost 

 all hatched b}' this time. Some had dried up and a few were found 

 just ready to hatch. A few were sticking out of the stalk and looked 

 quite fresh, but Avere probably infertile. Some of the leaves had 

 Avilted and died, and the remainder were literalh^ alive with small 

 to half-grown nymphs, together with a few adults, no doubt the 

 remaining parents. 



These half-grown nymphs Avere no doubt those hatched between 

 July 23 and 27, and would thus be between eight and eleven days 

 old. roughly indicating a nymphal period of between sixteen and 

 tAventy-tAvo days under these conditions. 



On August 14 this cage was visited again, and the beet found dead 

 and dry. From appearances it had been dead several days. The 

 fcAv leafhoppers that survived were adults and large nymphs. They 

 were so feAv in number that it Avas impossible to tell Avhether they 

 were the surviving parents or a neAv generation, so they were released. 



Cages 6 and 7 (silk scrim 2 feet square). — On July 23, 18 nymphs 

 A^arAing l)etAveen one-third and tAvo-thirds grown Avere introduced 

 into cage O. These Avere intended to represent the larger ones found 

 in the field at that date. 



On July 27 no adults could be seen. 



On August 3 most of the nymphs had changed to adults. This 

 period of elcA^en days was, then, more than one-third and slightly 

 less than two-thirds of the nymphal period. This gives about the 

 same result as the test in cage 4. 



Cages 8 and 9 (silk scrim Avith glass top). — On August 3, 40 leaf- 

 hoppers were introduced into cage 8; of these 23 Avere females, 

 55968°— Bull. 66—10 4 



