U. S. D. A., B. E. Bui. 63, Part III. C. B. W. I., February 5, 1907. 



PAPERS ON THE COTTON BOLL WEEVIL AND 

 RELATED AND ASSOCIATED INSECTS. 



AN ANT ENEMY OF THE COTTON BOLL WEEVIL. 



(Solenopsis geminata Fab. var. xyloni McC. ) 



By W. E. Hinds, 



In Charge of Cotton Boll Weevil Laboratory. 



INTRODUCTION. 



That native species of ants are the most important predatory ene- 

 mies of the boll weevil is an admitted fact, but the real extent of their 

 beneficial work has probably been underestimated rather than over- 

 estimated. Several species have been found attacking- the weevil in 

 some of its stages, but by far the most important one as yet observed 

 is a rather small species determined by Dr. W. M. Wheeler as 

 Solenopsis geminata Fab. var. xyloni McC. This ant is quite variable 

 in size and color, and the different forms found in Texas have been 

 separated into several varieties. As it is probable that the food 

 habits are similar in each of these forms, the varietal distinctions 

 need not be emphasized here. 



Doctor Wheeler has kindly furnished the following information: 



The species is common everywhere in the warmer parts of the world, and is both 

 highly carnivorous and highly vegetarian; that is, it will prey on any defenseless or 

 moribund insects, and stores seeds in the chambers of its nest. It stings very 

 severely, whence the name "fire-ant" or " Hormiga brava" which is given it in 

 Spanish America. The dark variety you sent is common in the black soil, such as 

 one finds in cotton fields. I have seen.it in great abundance in the vicinity of 

 Austin, Tex. 



DESCRIPTION, a 



» 



For the present purpose this ant may be characterized as follows: 



There are two distinct nodes or scales in the slender petiole of the abdomen. All 

 forms but the male have a sting. The antennae are ten-segmented; the club is 

 formed of the last two segments, of which the terminal one is the longer. Maxillary 

 and labial palpi have each two segments. The clypeus has two longitudinal ridges 

 and the sting is very large. The color varies, but the workers usually seen are of a 

 dark reddish brown, the color of the abdomen being often considerably darker than 

 that of the head and thorax. Length of workers from 2 to 3 mm. 



« For illustration of the species see Bui. 51, Bur. Ent., U. S. Dept. Agric, fig. 8, 

 p. 149. 



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