THE LARGER GRAIN-BORER. 
(Dinoderus truncatus Horn.) 
By F.. H. CHirrenpDEn, Se. D., 
In Charge of Truck Crop and Stored Product Insect Investigations. 
INTRODUCTORY. 
Brief mention has been made in a preceding article of the larger 
grain-borer (Dinoderus truncatus Horn) (fig. 9), in connection with 
the lesser grain-borer (Rhizopertha dominica Fab.). The larger 
grain-borer has without doubt been brought into this country from 
Mexico, Guatemala, and elsewhere on many occasions, but there are 
only a few published records of such importation. So far as the 
writer knows, the species has never found permanent lodgement in 
the United States, but is apt to be introduced into tropical Texas as 
well as elsewhere. It is not probable that it will be a very serious 
pest, provided its identity is known and efforts are made to stamp it 
out wherever it appears. From present knowledge of the insect’s 
habit, it would seem to differ but shghtly from the lesser grain-borer, 
preferring corn to other grain, if indeed it even feeds on any other 
cereal, and it also has the wood-boring habit strongly developed. 
Corn in the ear is preferred to shelled corn, and edible and other 
tubers and roots serve as natural breeding places. 
Attention has been called by the writer in correspondence to the 
difficulty of eradicating this species from a barn, if this should hap- 
pen to be constructed of wood or, what is worse, adobe. 
DESCRIPTION. 
Dinoderus truncatus is elongate cylindrical in shape and dark 
brown or castaneous in color, with paler legs and fulvous antenne. 
It measures one-sixth inch or less in length and is about two and a 
half times as long as wide. 
The genus Dinoderus (from two Greek words signifying /arge 
neck), in which this and the succeeding species are retained in our 
American works, was originally characterized by Stephens®@ as fol- 
lows: 
“Tilustrations of British Entomology, Mandibulata, vol. 8, p. 352, 1830. 
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