1923 



ENTOMOLOGICAL SOCIETY. 



51 



33 days, the average being 26 days; and the daily rate of deposition per female 

 varied from one to nine eggs. 



Fecundity. Quale, in California, found that the female leaf-hopper will 

 lay from 40 to 121 eggs. In our experiments with eleven couples, only the 

 eggs which actually hatched were counted (it was found to be impossible to do 

 otherwise without mutilating the insectary plants) and the results were as 

 follows: Maximum 89, minimum 38, average 70 eggs. 



Length of Life in Spring. In the insectary, females lived from 77 to 87 

 days after emerging from their winter quarters, and males from 63 to 78 days. 

 They commenced to die off about June 26th, and all had perished by July 20th. 



In the field the adults began to disappear during the latter part of June, 

 and most of them were gone by the second week in July. On account of the 

 overlapping of the first brood adults with the hibernating forms, we were unable 

 to ascertain just when the latter completely disappeared. 



Grape leaf hopper eggs laid in an 

 Ampelopsis leaf x 10. 



The Egg. 



Description. The egg is an elongate, slightly bean-shaped, soft body. 

 It is translucent creamy white in colour, and measures .63 mm. to .70 mm. 

 long, by .16 mm. to .20 mm. wide. 



Location. As previously mentioned, the eggs are inserted just beneath 

 the epidermis chiefly on the underside of the leaf, and on any part of the leaf 

 surface. As many as one-hundred to over five hundred eggs may be deposited 

 in a single leaf. They are generally laid singly; the variety ziczac, however, 

 commonly lays its eggs in parallel rows with three to ten eggs in each group. 



On smooth-leaved varieties of grapes and on the leaves of Ampelopsis, the 

 eggs cause little blisters to form, and these egg blisters make it a very simple 

 matter to locate the eggs with the unaided eye. However, on most common 

 varieties of grapes, the eggs are completely hidden from view by dense pubescence. 



Period of Incubation. In seven experiments with approximately 200 

 eggs of the first brood, and in nine experiments with about 200 eggs of the second 

 brood, the period of incubation varied only slightly, viz., from 25 to 27 days. 



Duration of Egg-hatching Period. The period during which the eggs 

 of the first brood hatched extended from June 19th, at which time the grape 

 was coming into full bloom, to about July 24th. The majority of the eggs 

 hatched before the second week of July. In table No. 1, the hatching of the 



4 E.S. 



