August, '22] BEYER: BEAN LEAF HOPPER 299 



northern part of the state, occuring on cowpeas, was August 20th. 

 Thus it is evident that the conditions regarding seasonal history differ 

 widely in Florida. 



Seasonal History 



The Bean Leaf-Hopper was first found feeding in the field on March 

 8, where it was collected abundantly on the poke weed {Rivina humilis) 

 which was growing in fence comers. The Adult stage was observed 

 feeding on the lower foliage and the largest percentage of those recorded 

 were females, however a considerable number of over-wintering males 

 still remained. In fact some mating was observed from these individuals. 

 The females were placed in small, glass cylinder cages one inch in diame- 

 ter, well ventilated and containing small plants for food, where they 

 could be kept unSer close observation with hand lens and binocular. 

 Egg scars were first found on the leaves March 10, and on March 18 

 the first nymphs were recorded. 



Following is a series of generations as recorded in the outdoor labora- 

 tory at Gainesville during 1921 : 

 Experiments : 



March 11 May 2 52 



May 2 June 20 49 



June 20 August 5 46 



August 5 Sept. 30 56 



Sept. 30 Nov. 28 60 



Nov. 28 Dec. 15 Feb. 27th, 1922 



Making a total of six generations for the season. 



The maximum number of nymphs produced per female 131 

 The minimum " " " " " " 22 



The average " " " " " " 59.3 



The length of life of the adult ranged from 32 to 64 days during summer 

 flight. The incubation period ranged from 5 to 9 days. 



The Influence of Climatic Factors 



The temperature for the year of 1921 reached a maximum of 101 

 degrees F. during June and a mean maximum of 86.3 for the season, 

 which was above the normal temperature for the latitude of Gaines- 

 ville. The summer was dry and hot with the exception of June which 

 had about a normal precipitation of 5.70", while July was above normal 

 having a rainfall of 15.03", and October with 6.03" was about normal. 



Since the Bean Leaf -Hopper has been recorded as reaching its optimum, 

 development during hot dry weather, it is evident that this species 

 experienced a quite favorable season for its development, however > 



