154 



dilute kerosene emulsion. The tarred- shield method in use against the 

 leaf-hoppers of the family Jassidse, and particularly the Typhlocibins 

 of Erythroneura and allied genera, will not avail here, since, as already 

 indicated, the insects do not fly out from the plant when disturbed, as 

 does the Grape Leaf-hopper, for instance, but simply hide behind the 

 stalk or twig upon which they have been feeding. 



Where '^ sharp-shooter" work is prevalent in a cotton field it will 

 probably pay to make a single application of the emulsion to the young 

 poplar growth along the borders of the field about the second week in 

 May. Many individuals will thus be killed which would otherwise mi- 

 grate to the cotton plants and lay their eggs for a new generation. It 

 will also pay the cotton-grower to cut down a large part of the young 

 poplar growth along the streams and bayous, so as to concentrate the 

 insects as much as possible. It is important to note in this connection 

 that the insect is absent, or very rare, in cotton fields which are not 

 contiguous to poplars. The insect wiU always be difficult to fight on 

 account of its numerous food-plants, but a restricted garden crop like 

 asparagus, of sufficient value to warrant the expense, can be protected 

 by an occasional thorough spraying. 



The discharge of drops of liquid by the pupa and adult is a most in- 

 teresting habit and is common to a large number of leaf-hoppers of the 

 family Cercopidee, varying, however, in degree. Proconia undata and 

 the species under consideration seem to have been most frequently no- 

 ticed, both on account of their more copious discharge and on account 

 of the abundance of the insects. The liquid is thrown out from the 

 anus in several small drops, frequently in an almost continuous spray. 

 The discharge is most copious when the insect is disturbed, and there 

 seems to be an effort to throw it in the direction of the intruder, so that 

 it probably acts as a defense against natural enemies, ^o scientific 

 observations have been made upon this secretion. It is too abundant to 

 be secreted by si)ecialized glands, and it is doubtless simply the excre- 

 mental fluid of the insect. It is rather whitish when it diies upon 

 leaves below the insect, and is slightly saccharine, although it does not 

 seem to have as great an attraction to bees, wasps, and ants, and other 

 honey-lovers, as does the secretion of plant-lice and certain of the larger 

 scale-insects. 



In Insect Life (vol. i, pp. 52-54) we have published in fuU the cor- 

 respondence with Mr. Bielby referred to above. Mr. Bielby's observa- 

 tions have been very careful and he gives an interesting account of the 

 habits of the adults with some details regarding the liquid secretion. 

 In volume ii (pp. 160-161) we noticed a newspaper article regarding 

 weeping trees, the remarkable phenomenon proving to be caused by 

 the abundance of Froconia undata^ while in volume iii (p. 415) we pub- 

 lished an interesting account of another weeping tree from a Missis- 

 sippi correspondent, Mr. E. J. McGuire. 



