84 PLANT-BUGS INJURIOUS TO COTTON BOLLS. . 



PENTATOMID BUGS OF THE GENUS THYANTA. 



(Plate I, fig. 4; text figs. 17 and 18.) 

 IDENTITY AND HISTORY OF SPECIES CONCERNED. 



The writer has carefully examined a series of over 80 specimens 

 which appear to represent a single species of the genus Thyanta and 

 finds that the variation is so wide that while the majority are undoubt- 

 edly T. custator as described by Fabricius, several agree fairly well 

 with the original description of T. perditor Fab. and T. casta Stal. 

 Variations are found in size, form of humeral angles, proportionate 

 lengths of the segments of the antennae, and color and markings of 



the body, antennae, and wing membranes, 

 which might readily be mistaken for spe- 

 cific characters. 



These latter two species — if in fact they 

 are valid — have not as yet been suffi- 

 ciently characterized to distinguish them 

 from the variations of the insect gener- 

 ally recognized as Thyanta custator Fab. 

 Injury to crops by this species'* was first 

 recorded by Prof. E. D. Sanderson, who 

 reported its occurrence in 1903 in unusual 

 Fig. n.- Thyanta custator: Nymph, numbcrs in northern Texas, where it seri- 



firstinstar. Enlarged 27 diameters. ously iujurcd OatS, COm, and SOrghum, 



and was also found in numbers on milo 

 maize and cowpeas. The frequent occurrence of this insect on cotton 

 bolls has also been noted by Sanderson. 



DISTRIBUTION. 



Uhler states in regard to the distribution of Thyanta custator that 

 the species inhabits upper and lower California, Texas, Arizona, 

 Colorado, ''Dakota," and the Atlantic region generally from Quebec 

 to Florida.^ According to Mr. Van Duzee, it occurs in greatest 

 abundance tow^ard the South and West.*" In Texas it is one of the 

 most common Pentatomid bugs and is especially abundant in the 

 northwestern part of the State. Except in northern Texas and 

 Oklahoma, it seems to be of too rare occurrence on cotton to be 

 worthy of consideration as a pest. 



■ «At first determined as Thyanta perditor Fab. and afterwards redetermined as 

 T. custator Fab. Compare Bui. 46, Div. Ent., U. S. Dept. Agr., p. 94, 1904, with Bui. 

 57,-Bur. Ent., U. S. Dept. Agr., p. 49, 1906. 



& Bui. U. S. Geol. and Geog. Surv., No. 5, Second series, List of Hemiptera, p. 23, 1876. 



c Trans. Amer. Ent. Soc, XXX, p. 53, 1904. 



