GAEDEN FLEA-HOPPER IN ALFALFA. 21 



SPRING APPEARANCE AND NUMBER OF GENERATIONS. 



The adults of the garden flea-hopper in the latitude of Columbia, 

 S. C, usually appear about the middle of March. Much depends 

 upon the season, however, and they have been found soon after the 

 host plants become green and spring is well in evidence. The adults 

 appeared and deposited eggs as early as March 14, 1915, in the field 

 experiments at Columbia, which was the earliest date recorded of 

 the discovery of eggs in the outdoor experiments. Eggs have been 

 secured in the outdoor cages throughout the year, beginning Avith 

 the middle of March and continuing until the last of November. 

 From five to six generations were reared at the Columbia laboratory. 

 The length of life of each individual is determined largely by the 

 length of life of the adult stage, this being the longest period of the life 

 cycle. 



The first generation was found to extend from March 14, 1915, 

 when fertile eggs were first deposited, to May 15, 1915; the second 

 generation extended from May 15 to July 12, 1915; the third from 

 July 12 to September 11; the fourth from September 11 to November 

 18, and the fifth from November IS, 1915, to February 10, 1916. 



FEEDING HABITS. 



In almost every instance noted the youngest plants are attacked in 

 preference to the older and more vigorous growths; and when the 

 insects start feeding on a plant they apparently continue until all 

 the sap is extracted, giving the plant a bleached appearance. During 

 the warm seasons the tendency is to feed at the top of the plants, but 

 during cool days and seasons they feed rather at the bases of the 

 plants. It has been noticed that during warm days the individuals 

 seem to show no particular inclination for protection from the sun 

 by seeking the shady side of the leaf. When they are disturbed, 

 however, they immediately seek a place of concealment on the plant 

 or hop to the ground in quest of protection. 



In feeding on the host plant, the individual places itself in a posi- 

 tion parallel to the surface of the leaf, preferably on the upper surface, 

 with its legs resting on the surface. Then the proboscis is swung 

 down from the ventral side of th(> body to a perpendicular position 

 and the apex is thrust into the epidermis of the leaf at a point mid- 

 way between the pro thoracic legs, the proboscis is hinged at the 

 second articulation, the head and thorax being bent slightly dowTi- 

 ward to allow the first and tliirtl articulations to meet, the suckins 

 tube remains straight as the open sheaths of the second and third 

 segments leave the sucking tube, and a slight pressure is placed on 

 the apex of the proboscis. A mechanical procedure ensues similar 

 to the pumping process, in whicli the head and thorax move slightly 

 upward and dowTiward, not sufliciently, however, to strnightcMi the 



