SOUTHERN GREEN PLANT-BUG, 23 



Specimens of Nezara viridula accompanied the notes. At Dade 

 City, on November 11, an adult of the pentatomid bug Euthyrhynchus 

 floridanus was found with its rostrum thrust into a mature individual. 

 Bicytes quadrifasciata Say. — Mr. S. A. Rohwer of the Bureau of 

 Entomology states that a bembecid wasp which Mr. Russell collected 

 at St. Leo, Fla., October 22, 1907, belongs to this species. The 

 specimen was taken while in flight with an adult of Nezara viri- 

 dula grasped in its mandibles. 



CLIMATE AS A CONTROL FACTOR. 



Whitmarsh (13) considers climate an important factor in the 

 natural control of the related Nezara Mlaris in Ohio. Cold winters, 

 or periods of cold weather following unusually warm weather during 

 the winter months, killed many individuals of that insect. Observa- 

 tions made in connection with Nezara viridula in the Gulf States 

 indicate that sudden drops in temperature during the winter months 

 kill many individuals in the field. In Florida Mr. H. M. Russell 

 found, on December 5, 1907, "a few dead adults after the freeze" of 

 the preceding night. Writing from Brownsville, Tex., on May 25, 

 1909, Messrs. D. K. McMillan and H. O. Marsh stated that the 

 "species has been conspicuously absent for several months, though 

 very abundant during the fall and early winter * * * 5 ' and 

 added "It may be that the two freezes of January 15 and early 

 February may have had some influence." 



The writer has found that in the insectary at Baton Rouge indi- 

 viduals, especially in the nymphal stages, are sometimes killed by 

 low temperatures during the winter months. 



METHODS OF ARTIFICIAL CONTROL. 



It is well known that the pentatomid bugs and other large plant- 

 bugs are quite resistant to contact insecticides, and the experiments 

 indicate that it is difficult to control the southern green plant-bug 

 by using insecticides of this type. 



SPRAYING WITH NICOTINE SULPHATE. 



Individuals in various nymphal ins tars, as well as adults, have 

 been drenched with dilutions of nicotine sulphate which con- 

 tained 40 per cent of nicotine by weight in combination with 

 yellow laundry soap at the rate of 2 pounds to 50 gallons of water. 

 These individuals were then kept under observation in the insectary 

 and the effects of the different mixtures upon them noted. A 

 dilution of 1 part nicotine sulphate to 300 parts of water killed all 

 nymphs, but even in the proportion of 1 to 100 the nicotine had 

 little effect on the adults. A dilution of 1 to 600 was not effective 

 against nymphs in the third, fourth, and fifth instars. On the 



