Jan. 15. I9IS Three-Cornered Alfalfa Hopper 359 



this is a serious pest to late summer crops. The insects are so thick at present that 

 when a man is walking through alfalfa they fly into his face and swarm ahead of him 

 like bees. 



During the early part of September, 1914, several complaints were re- 

 ceived from southern Virginia by the United States Department of Agri- 

 culture of serious damage to alfalfa by the insect under discussion. One 

 such infestation occurred at the county experiment station at Williams- 

 burg, Va. In this case Mr. R. P. Cocke reported that fully 95 per cent 

 of the plants were seriously affected by the characteristic girdling of the 

 hopper. Specimens of the insect were sent to the Department for iden- 

 tification and found to be the three-cornered alfalfa hopper in its fourth 

 nymphal instar. 



DAMAGE TO PLANTS OTHER THAN ALFALFA 



In Mississippi Mr. Gibson has found that this hopper does as much 

 damage to cowpeas as it does to alfalfa, or more. He finds that the 

 greatest damage comes when the cowpeas are small, possibly only two or 

 four leaves having developed. In this case, when the plant is girdled it 

 can not so well overcome the damage and usually wilts down immedi- 

 ately. Often as many as 15 nymphs would congregate on one cowpea 

 plant and soon sap its life. One of the serious causes of injury to cow- 

 peas is the oviposition of the females. As has been stated elsewhere in 

 this paper, the eggs are laid in pockets in the stems of the cowpeas, and 

 around these pockets galls often develop. The scars resulting from 

 such action are often so large and so abundant — as many as eight on a 

 single small plant—that the plant is greatly retarded in growth and may 

 break off or die. 



Dr. A. W. Morrill, State Entomologist of Arizona, has told the writer 

 that in their work with bean insects they have discovered Stictocephala 

 festina in large numbers on beans and probably doing quite a bit of dam- 

 age. The writer has made no observation of the pest on these plants. 



Although a great many other plants are fed upon by this insect, none 

 of them seems to be greatly damaged. While Dr. Oemler, in 1887, 

 reported (4) damage to tomato plants, there seems to be no record since 

 that time of any damage to that crop, and the species has certainly not 

 become of great importance in relation to tomato culture. 



NATURAL ENEMIES OF THE ALFALl'A HOPPER 



During the study of the three-cornered alfalfa hopper as an alfalfa 

 pest it has been shown that it suffers in a remarkably small degree from 

 natural enemies. Prof. T. D. A. Cockcrell in 1899 observed (9) a spider, 

 Argiope transversa Emerton, feeding on the alfalfa hopper at Phoenix, 

 Ariz. The writer has also noticed remains of the insect in spider webs 

 in alfalfa fields, but these do not exert any remarkable influence in re- 

 ducing the numbers of the pest. Likewise, the harvester ant {Pogono- 

 myrniex barbatus Smith) has been noticed by both the writer and Mr. 

 Gibson carrying individuals of Stictocephala festina, but these must have 

 been dead or disabled before capture by the ants. A small red prcdaceous 

 mite, Erythraeus sp., was found feeding upon the eggs, choosing those 

 with the outer end protruding above the plant tissues. Dr. O. C. Bart- 

 lett, Assistant State Entomologist of Arizona, informs the writer that 

 in his work with this insect as a bean pest he has reared large numbers 



