LEAFHOPPERS OF THE SUGAR BEET. 39 



Cages ^ and 5 (glass globes upon beets about S inches in diam- 

 eter).— On July 10, IG adult leaflioppers, 12 of Avhich wore females, 

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

 females AA-ere bearing eggs, and the presence of a A^ery fcAV small 

 nymphs in the field proA'ed that the earliest ones began depositing 

 eggs some time before. It AA-as therefore expected that some of the 

 females introduced Avould begin depositing at once. 



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

 the leafhoppers the stems aa^m-c found to be fairly covered Avilh (^g^ 

 scars. Taa'o of the stems Avere removed and i^reserved, and found to 

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

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



July 27 the stems shoAved still more ^gg scars, and there Avas quite 

 a number of small nymphs that had apparently been out several 

 days. The insects had been in the cage only scA^enteen days, so these 

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

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

 Avas remoA'ed and preserved, and the rest left as before. 



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

 all hatched by this time. Some had dried up and a fcAv Avere found 

 just ready to hatch. A fcAv Avere sticking out of the stalk and looked 

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

 Avilted and died, and the remainder A\'ere literalh^ aliA'e Avith small 

 to half-groAvn nymphs, together Avith a feA\^ adults, no doubt the 

 remaining parents. 



These half-groAvn nymphs Avere no doubt those hatched betAveen 

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

 old, roughly indicating a nymphal period of between sixteen and 

 twenty-tAvo days under these conditions. 



On August 1-4 this cage was visited again, and the beet found dead 

 and drA^ From a jjpea ranees it had been dead several days. The 

 fcAv leafhoppers that survived Avere adults and large nymphs. They 

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

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



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

 A'arA'^ing betAveen one-third and tAvo-thirds groAvn were introduced 

 into cage C. 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 Avas, then, more than one-third and slightly 

 less than tAvo-thirds of the nymiihal ])eriod. This gives about the 

 same result as the test in cage 4. 



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

 hoppers were introduced into cage 8; of these 23 Avere femak^s. 



G6— IV 



