22 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



In his brief experience as an entomologist, the writer has not en- 

 countered or heard of any species which exercises its destructive 

 abilities in so many different directions. As a household pest I ven- 

 ture the opinion that this ant has no equal in the United States. It 

 is both a direct and indirect enemy of horticulture; direct by actual 

 destruction of buds, blooms and fruit, and indirect by its fostering 

 care of various scale insects and plant lice. In the latter role it be- 

 comes also an enemy of importance to shade and ornamental trees and 

 plants. By its association with Pseudococcus calceolariae (Mask) it 

 may wipe out, or at least make unprofitable, the production of cane 

 sugar in the South. By its successful antagonism of beneficial forms 

 it becomes doubly injurious. The varieties of Solenopsis geminata, 

 now regarded as extremely important in the natural control of the boll 

 M^eevil, are likely to be greatly reduced in numbers by Iridomyrmex 

 humilis and thus the latter species may become the indirect cause of 

 damage to the cotton crop. Even as a menace to human life, under 

 certain circumstances, this little ant cannot be entirely ignored. To 

 this I shall refer later. 



History and Introduction. 



The species was first described as " Hypoclinea humilis" by G. 

 Mayr, in 1868, from workers collected in 1866 near Buenos Ayres in 

 Argentina, the original description appearing in the Annuario delta 

 Soc. Naturalisti Modena, Vol. Ill, page 164. Following is Mayr's 

 description of the species, kindly furnished by Dr. W. M. Wheeler of 

 the American Museum of Natural History, from the original edition : 



"Operla : Long, 2.6 mm. Sordide ferruginea, micans, mandlbularum parte 

 apicali flavescenti, abdomine nigrofusco, tarsis et nonnunquam tibiis testaceis ; 

 miscroscopice adpresse pubescens ; absque pllis abstantibus ; subtilissime 

 coriaceo-rugulosa, mandibulis nitidis sublaevigatis pimctis nonnuUis; clyi)eus 

 margine antico late baud profunde emarginatus ; thorax inter mesonotoni et 

 metanotum paulo et distincte constrictus, pronoto fornicato, mesonoto longi- 

 trorsum recto, transversim convexo, metanoto inermi longitrorsum fornicato, 

 pronoto paulo altiori ; petioli squama compressa rotundata." 



No mention of this species in the literature on economic entomology 

 seems to have appeared prior to the publication of a paper by E. S. G. 

 Titus, of the Bureau of Entomology, in the proceedings of the Seven- 

 teenth Annual Meeting of this Association,* reciting his observations 

 made upon a trip to New Orleans in July, 1904, at the request of 

 Prof. H. A. Morgan, who prior to that time, had recognized the dan- 

 gerous nature of the pest. Mr. Titus's paper is replete with inter- 



aBulletin No. 52, Bureau of Entomology, U. S. Dept. Agr., p. 78-84. 



