20 



BULLETIN 964, U. S. DEPARTMENT OF AGRICULTURE. 



NUMBER AND LENGTH OF INSTARS. 



There are five instars. The length of the instars as well as the 

 total length of the nymphal life is slightly variable, as may be noted 

 by reference to Table V. What slight variations there were in the 

 length of these instars may have been due, in large measure, to differ- 

 ences of temperature and food supply. 



The intervals between each two instars gradually increases as 

 maturity is reached. There was found to be no relation between 

 the length of the periods and the sex of the individual. 



LENGTH OF LIFE OF THE ADULT. 



Adults of Halticus citri lived for from 9 to 94 days in the rearing 

 experiments, as is shown in Table VIII. The sexual development 

 was found to be complete as soon as they became adults. The 

 females are shown to have lived longer than the males. 



Table VIII. — Length of life of adults of Halticus citri. 



No. 



Male. 



Female. 



Emerged. 



Died. 



Days. 



Emerged. 



Died. 



Days. 



1 



2 



3 



4 



5 







7 



8 



9 



July 10 

 July 13 

 July 10 



...do 



July 13 

 Aug. 17 

 Aug. 18 

 Oct. 27 

 ...do 



Aug. 9 

 Aug. 26 

 July 19 



...do 



July 26 

 Aug. 30 

 Sept. 10 

 Dec. 22 

 Jan. 29 



30 

 44 

 9 

 9 

 13 

 13 

 23 

 26 

 94 



July 13 



...do 



July 15 

 July 12 

 Aug. 15 

 Aug. 17 

 Aug. 31 

 Oct. 27 

 Oct. 28 



Aug. 29 

 Aug. 10 

 Aug. 31 

 Aug. 6 

 Sept. 10 

 Sept. 2 

 Nov. 3 

 Jan. 13 

 Jan. 16 



42 



28 

 47 

 25 

 20 

 16 

 64 

 78 

 70 





Av. 



29.3 



44 











HIBERNATION. 



In experiments carried out by the writer, the last remaining indi- 

 viduals of the adults which had emerged on October 27, 1915, died 

 on January 29, 1916. Other adults of both sexes issued December 

 18, 1915, and hibernated until March 14, 1916, when they became 

 active again. Eggs were found in the cage on this date. First- 

 stage nymphs w^^re discovered on April 2, 1916. 



The garden flea-hopper .is found in greatest abundance during 

 August and September, and gradually decreases in number as winter 

 approaches. In the latitude of Columbia, S. C, mortality is greatest 

 in December, very small numbers being found after this date. Many 

 of the adults apparently are killed by the cold weather, and the 

 remainder seek winter protection under the thickest bunches of their 

 favorite host plants, along fences and other well-protected places, 

 where they continue to winter until the plants become green again 

 in the spring, and then deposit eggs before perishing. 



