STUDIES ON PERILLUS BIOCULATUS FAB. 
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1907 Perilloides bioculatus Schoutedon, Genera Ins., Fasc. 52, p. 37. 
1909 Perilloides bioculatus Kirkaldy, Cat. Hemip. Heterop., i, p. 6. 
1910 Perillus bioculatus Banks, Cat. Hemip., p. 95. 
1912 Perilloides bioculatus Zimmer, Univ. Nebr. Studies, x1, p. 234. 
1917 Perillus bioculatus Van Duzee, Cat. Hemip., p. 73. 
1917 Perillus bioculatus var. clanda Van Duzee, Cat. Hemip., p. 74. 
1919 Perillus bioculatus Hart, Bul. Il. Nat. Hist. Surv., viti, p. 198. 
1920 Perillus bioculatus Stoner, Univ. lowa Stud. Nat. Hist., vii, No. 4, p. 117. 
History and Distribution 
The original home of Perillus bioculatus appears to have been the 
eastern slopes of the Rocky Mountain region. From there it has 
migrated eastward, apparently following the movement of the Colorado 
potato beetle, which forms its natural food. Thomas Say (1825) des- 
cribed this species from material collected during the expedition of 
Major Long to the Rocky Mountains, and altho the author states 
that the species “inhabits Missouri,” the specimens described were 
probably collected in the western part of that territory. 
What appears to be the first published account of Perillus bioculatus 
as a beneficial insect feeding on the Colorado potato beetle, is given 
in a bulletin by Howard (1900). This record is in the form of a 
letter, which was accompanied by specimens, from Mr. J. A. Green, 
Waynoka, Oklahoma. The letter, dated September 16, 1899, describes 
the feeding habits of Perillus on the Colorado potato beetle, with notes 
on the life history and relative abundance of the species. 
An unpublished account of observations on Perillus bioculatus was 
recently related to the writer by Dr. H. B. Hungerford. He states 
that as a small boy, during the summer of 1896, when living near 
Fairbury, Neb., it was his task to rid the potato vines of the Colorado 
potato beetle. Then it was that he became acquainted with a con- 
spicuous stink-bug, black in color and varied with white, yellow, or 
red, which was present in some numbers feeding on the potato beetle. 
The predaceous habits of these bugs proved of such interest that speci- 
mens were placed in cages where he fed them daily with grubs and 
adults of the potato beetle. 
The eastward movement of Perillus bioculatus is reflected to a 
certain extent in the writings of various entomologists who have 
noticed the predaceous habits of the bug in its relation to the Colorado 
potato beetle. 
Osborn (1892) listed Perillus bioculatus from Iowa, and indicated 
that it occurred rarely in the state. Stoner (1920), in a comprehen- 
sive account of the Scutelleroidea of Iowa, records only three speci- 
