Nov. is, 1920 Life History and Habits of the Beet Leafhopper 247 



LIFE HISTORY AND HABITS 

 ' REPRODUCTION 



During the summer season mating occurs within a few days after the 

 last molt is accomplished, but during the fall this period is greatly pro- 

 longed. In Idaho adults were observed copulating in cages during the 

 late fall as well as during the summer season. At Spreckels, Calif., 

 mating continued throughout the winter. Unfertilized females have 

 been known to lay sterile eggs under certain conditions, but partheno- 

 genesis has never been observed. 



The preoviposition period is comparatively long. In all experiments 

 15 to 17 days elapsed between the date the female reached maturity and 

 the date the first eggs were laid. A much longer period is common, 

 especially during the winter and early spring. 



OVEPOSITION 



Under normal conditions the eggs of the beet leafhopper are usually 

 placed in the petiole or midrib of the sugar-beet leaf, beneath the fibrous 

 strands and at a slight angle. They are invariably deposited one at a 

 time, but often they are arranged in rows of from two to five, placed end 

 to end so that they give the appearance of overlapping. It is almost 

 impossible to find the recently deposited eggs in the petioles; but after 

 the embryo has developed a little and the eye spots have appeared they 

 are comparatively conspicuous. When, deposited in the leaf tissue the 

 eggs are more easily detected by the raised areas on the leaf surface. By 

 transmitted light eggs in this position appear as small, transparent slits. 



While apparently preferring the sugar beet as a plant in which to 

 deposit its eggs, this leafhopper will oviposit in a large number of other 

 plants. Fleshy or succulent species offer the most suitable conditions 

 for oviposition. Russian thistle (Salsola kali var. tenuifolia), filaree 

 (Er odium cicutarium and E. moschatum) , Chenopodium spp. (especially 

 murale), and Atriplex spp. are plants from which eggs have been most 

 commonly noted hatching under natural conditions. Most perennial 

 plants are too tough and woody to be suitable for this purpose, and it is 

 doubtful if they are of any great importance as hosts during the egg- 

 laying period. 



Ball (2, p. 40) records the number of eggs deposited by a single female 

 of this species as about 80. At Spreckels, Calif., the maximum number of 

 eggs deposited by one female was 237, while at Riverside, Calif., the maxi- 

 mum was 247. Many difficulties were encountered in the conduct of 

 these experiments, and it is probable that, given more favorable condi- 

 tions, the females might have deposited a larger number of eggs. 



Meteorological conditions influence greatly the incubation period. A 

 maximum period of 52 days has been observed during the early spring 

 and a minimum of 10 under most favorable conditions. During the 



