2 DEPARTMENT BULLETIN 1779. 
Weather influences and the work of parasites in each locality where 
damage has occurred generally have restricted the destructive out- 
breaks of C. sayi to periodic intervals of two or three years. Since 
1911, however, its activities have been reported with increasing fre- 
quency each year in widely separated districts within its range. 
This development indicates clearly the possibility that the species 
may become economically more important in the future than it 
has been in the past. 
HISTORY. 
The grain bug belongs to the rather extensive heteropterous family 
Pentatomidae, the members of which are popularly known by the 
expressive term of “stink-bugs.” It was first authentically described 
under the name Lioderma, subg. Chlorochroa, sayi by Stal (1)* in 
1872. In the same year Uhler (2) described a species under the name 
Pentatoma granulosa, which later proved to be synonymous with 
Stal’s ZL. sayi. In 1904 Van Duzee (3) placed the species in the sub- 
genus Chlorochroa of the genus Pentatoma. In 1909 Kirkaldy (4) 
placed the subgenus Chlorochroa under the genus Rhytidolomia. In 
1916 Van Duzee (7) removed Chlorochroa from Rhytidolomia and 
raised it to generic rank, listing the species under consideration as 
Chlorochroa sayi Stal. 
The first recorded damage by Chlorochroa sayi is found in the un- 
published notes of the Bureau of Entomology, several farmers of the 
upper Gila and Salt River Valleys of Arizona having reported it, in 
May, 1903, as very destructive to wheat and barley. One farmer 
wrote that there was an average of about 10 bugs to each head 
of barley in his 40-acre field. After badly damaging this area 
the insects had moved to an adjoining wheat field, these con- 
ditions being typical for a distance of about 30 miles along the 
upper Gila Valley. In reply to an inquiry by Dr. L. O. Howard the 
following note was received on June 5, 1903, from Dr. R. H. Forbes, 
director of the Arizona Agricultural Experiment Station: “* We 
have kept track of the outbreak of Lioderma sayi in Arizona. The 
worst outbreak was upon the upper Gila River, between Safford and 
Fort Thomas, but a great many specimens were also to be found 
in the Salt River Valley.” In July of the same year reports of dam- 
age and specimens of the insect were received from the San Juan 
Valley in southwestern Colorado. In 1905 and 1906 this species 
was very numerous in the wheat fields of northern Texas, but no 
widespread damage was reported. Dr. A. W. Morrill (6) published 
an account of the complete loss of 13 acres of milo maize near 
Phoenix, Ariz., in September, 1911, as a result of depredations by 
1 Figures in parentheses refer to ‘‘ Literature cited,’”’ p. 34. 
