June, '08] jourxai. ob' economic entomology 183 



follows : First stage, four days ; second stage, two days ; third stage, 

 three days ; fourth stage, four days, and fifth stage, five days. Total, 

 eighteen days. 



The same insect in New York, as has been determined by Slinger- 

 land, requires from thirty to thirty-three days for its nymphal devel- 

 opment. There is then a difference of two weeks in the time of devel- 

 opment of the grape leaf -hopper in New York and that of the same 

 insect in California. This difference is generally attributed to cli- 

 mate, although there is little difference between the climate of upper 

 San Joaquin Valley in California in June and July and that of New 

 York in the same months. 



During the last week in June the hoppers, arising from the eggs of 

 the over-wintering hoppers laid in May, begin egg laying, which is 

 continued through July and a part of August. The incubation period 

 was noted for a hundred or more eggs and they all hatched in from 

 eight to twelve days. This is a shorter period than was required for 

 the eggs to hatch in May from the over-wintering insects, and may be 

 due to the difference in temperature. 



A number of hoppers were confined in individual breeding cages on 

 the leaves of the grape, and the number of eggs laid varied from forty 

 to one hundred and twenty-one, distributed over a period of from 

 three to seven weeks. 



Hoppers hatching from these eggs remain on the vine until the 

 leaves fall, when they attack their winter food plants, which include a 

 large number of plants that may be growing in the vineyard or 

 vicinity. These attack the vine in the spring, begin egg laying in 

 May, and die off in July, making the length of the life cycle approxi- 

 mately one year. The spring brood hatching in May lives until about 

 August or September, thus completing the life cycle in three or four 

 months. There are thus two broods of the grape leaf-hopper in Cali- 

 fornia, and, at least during the past year, there was no indication of a 

 third brood. 



NOTES OF THE SEASON 



By H. A. GossARD, Wooster, Ohio 



The season opened with a noteworthy weather condition that seems 

 to have had a perceptible effect on the development of San Jose scale. 

 March 19 the mercury rose to 68° at Wooster, and the following 

 maximum temperatures were recorded at this place during the next 

 two weeks : 



