December, '22] severin and basinger: beet leafhopper 417 



Little Panoche Valley. — ^An examination was now made of the 

 mountain passes and a remarkable discovery was made on April 20, 

 1920. Hundreds and hundreds of pale green leafhoppers were swarm- 

 ing at sunset on Red Stem Filaree on April 24, in Little Panoche Valley 

 into which the entrance of Panoche Pass opens from the middle section 

 of the San Joaquin Valley. During the calm evening on April 28, the 

 adults were common in the air at dusk; the hoppers assembled on the 

 automobile and mating was observed. The flight of the insects could 

 not be followed to any great distance on account of the approaching 

 darkness, but they flitted about everywhere. Investigations were 

 made from the mouth of Little Panoche Valley following the river 

 benches of Little Panoche Creek via Mercey Hot Springs to the simimit, 

 a distance of 12 miles, and swarms of pale green specimens flew about at 

 sunset when the pasture vegetation was swept with an insect-net. 

 Enormous nimibers of spring brood forms were found in Little Panoche 

 Valley to the foot of Ortigalita Peak. 



Panoche Valley. — Investigations were conducted in Panoche 

 Valley, situated between the two Coast Ranges, but the bugs were not 

 abundant on Red Stem Filaree growing in the cultivated fields. When 

 the hills are covered with shrubs and trees, as is the case on the second 

 interior Coast Range, beet leafhoppers are very rarely captured on 

 Red Stem Filaree. 



Panoche Hills.— During 1920-1921, the investigations were ex- 

 tended to the Panoche Hills bounding the San Joaquin Valley. The 

 dark overwintering adults were common on the Panoche Hills but 

 specimens were rarely taken on the Griswold Hills not bounding the 

 San Joaquin Valley and to the south of the Panoche Hills. During the 

 winter the insects were most abundant on the sunny slopes of the hills. 



A trip encircling the Panoche Hills was taken; nymphs and an occa- 

 sional spring brood adult were taken on the hillsides along Little Panoche 

 Creek as early as March 17. Nymphs and first brood adults were more 

 abundant on the hillsides along Big Panoche Creek, situated about 10 

 miles southeast of Little Panoche Creek, indicating an earlier develop- 

 ment. It was evident that a marked reduction of the overwintering 

 females had ocaured due to the fact that they were at the end of their 

 natural life, having deposited their eggs and died. 



An interesting observation was made during April. Large numbers of 

 pale green adults were found on the sunny slopes of the Panoche Hills 

 on April 6 where the dark overwintering forms were found during the 

 winter. As the Red Stem Filaree became dry on the hillsides a move- 

 ment up to the crest of the hills and down to the floor of the canyons 



