April, '10] GILLETTE : INSECTICIDES FOR Al'HlDS 207 



The Argentine Ant {Iridomyrmex humilis Mayr) ranks first among 

 the Louisiana predaceous enemies of the JMidge. This ant has not 

 been found by the writer in Texas. The Argentine Ant in Louisiana 

 attacks the Midge when the latter is in the pupa projecting from the 

 apex of the seed just prior to the emergence of the adult. In this 

 position it falls a ready prey to this enemy which seizes the pupa 

 between its mandibles and draws it from the seed. . 



In Louisiana and also in Texas the writer has observed the fly, 

 Psilopodinus flaviceps Aldrich, capture the adult midge when the 

 latter is crawling over a seed head preparatory to ovipositing. 



Several species of Odonata have been observed by the writer evi- 

 dently capturing adults of the midge as the latter swarm about the 

 seed heads although actual dissection of the stomachs of these flies 

 has not been made in order to settle this point definitely. 



SOME INSECTICIDE TESTS FOR THE DESTRUCTION OF 

 APHIDIDAE AND THEIR EGGS 



By C. P. Gillette, Ft. ColUm, Col. 



For some years past I have been making comparative tests of dif- 

 ferent insecticides for the destruction of plant lice (Aphididce) and 

 their eggs. The object of this paper is to announce a summary of 

 the more important results only. I shall not even take time or space 

 to refer to the work that others have done along the same lines. 



The more important substances used have been emulsions, soaps, 

 lime-sulfur preparations, and tobacco extracts in which nicotine is 

 supposed to be the only active agent. 



For the Destruction of Eggs 



Kerosene emulsion was used in 35 different tests. In 8 of these 

 no eggs were found hatched. Of the 27 applications which did not 

 fully prevent hatching, 19 were above 16% oil, 8 were above 33% 

 oil, and 2 were 50% oil. With less than 25% oil in the emulsion the 

 eggs seemed to hatch as well as those imtreated. Eggs of 4 species, 

 Aphis ponii, A. vihuniicola, ChaitopJiorus negundinis and Melano- 

 xanthenum smitliw, were used. 



Scalecide w^as used in proportions varying between 5 per cent and 

 25 per cent. Eggs hatched from 20 out of 22 treatments and from all 

 strengths. 



Thompson's Soluble Oil was used in 14 tests and in strengths 



