1923 ENTOMOLOGICAL SOCIETY. 55 



Time of Occurrence of First Brood Nymphs. Newly hatched nymphs 

 were first observed on June 19th, at the time grapes were coming into bloom. 

 From three to ten nymphs to a leaf, the number rapidly increased until by the 

 end of June 200-300 nymphs could be found on a leaf. During the first and 

 second weeks of July, the inner and lower leaves on the vines were literally 

 alive with nymphs — on leaves picked at random from 500 to 800 nymphs to 

 a leaf were counted. 



As shown in table No. 1, the nymphs continued to hatch out until about 

 July 24th, and it was not until the latter part of August that all the nymphs 

 of the first brood matured. 



Time of Occurrence of Second Brood Nymphs. Second brood nymphs 

 first appeared on August 15th ; they continued to hatch out until about September 

 10th, and all had transformed to adults by October 9th. 



The Summer Adult 



Description. Say's description is as follows: 



"Body pale yellowish ; head, a transverse sanguineous line, profoundly arcuated in the middle* 

 and a smaller transverse spot before; eyes fuscous; thorax with three sanguineous spots, the lateral 

 ones smaller, and the intermediate one arcuated; scutel, a sanguineous spot at tip; hemelytra 

 yellowish white spotted with sanguineous; spots arranged two at base, of which the outer one is 

 small and the inner one elongated and abruptly dilated on the inner side at tip; two upon the 

 middle, of which the outer one is elongated in a very oblique line; two behind the middle, of which 

 the inner one is obliquely elongated, and the outer one smaller and interrupted; and a transverse 

 linear one near the tip, ramose upon the nervures; feet whitish. 



"Length to the tip of the hemelytra one-ninth of an inch. 



"The line and spot on the head and the spots of the thorax are sometimes obsolete, but always 

 visible, and the latter are sometimes connected by curving toward the anterior edge of the thorax. 

 The spots of the hemelytra are also sometimes slightly interrupted, or connected into four oblique 

 bands." 



Colour Changes. During the summer the colour markings of the adults 

 are yellowish. With the approach of autumn the coloured areas become salmon 

 or light reddish, and when the insects go into hibernation the markings deepen 

 into a conspicuous blood red, which colour is maintained throughout the winter. 

 However, when the adults emerge in spring and begin to feed on the grape this 

 colour fades to the light yellow, characteristic of the summer adults and remains 

 light throughout life. 



Egg Laying. In insectary experiments with six first brood couples, ovi- 

 position commenced six to nine days after the adults reached maturity, the 

 average pre-oviposition period being seven days. Each female deposited from 

 22 to 46 viable eggs, the average being 29 eggs.* The period of oviposition 

 of the individual varied from eleven to twenty-two days. As determined by 

 subtracting the incubation period from the dates when the earliest and last newly 

 hatched nymphs appeared, the egg-laying period of first brood adults in the 

 vineyards extended from about July 20th to August 17th. 



Length of Life. The adults which give rise to a second brood succumb 

 before winter; the others go into hibernation, and, as previously stated, many 

 of them survive until the following July. In the insectary all second brood 

 progenitors perished before the end of September. The females lived from twenty 

 six to forty-seven days with an average length of life of thirty-eight days, and 

 the males from six to seventeen days, the average being fifteen days. 



Proportion of Sexes. The males and females of this species are practi- 

 cally equal in numbers. In a collection of 2827 leaf hoppers captured in different 

 vineyards throughout the district, the sex ratio was 48 males, 52 females. 



*It should be mentioned that here again only the eggs which actually hatched were counted. 



