U. S. D. A., B. E. Bui. 06, Part TTI. T. C. & P. I. I., March SI, 1911. 
PAPERS ON INSECTS AFFECTING STORED PRODUCTS. 
THE LESSER GRAIN-BORER 
(Rhizopertha dominica Fab.) 
By F. II. Chittenden, Sc. D., 
In Charge of Truck Crop and Stored Product Insect Investigations. 
INTRODUCTORY. 
Among insects which inhabit granaries and storehouses, and which 
feed upon dry cereals, are two species of beetles of the family Bostry- 
chidae, which are of considerable importance in tropical climates, but 
are fortunately seldom seriously injurious in colder countries. 
On account of their boring proclivities, the writer has termed 
these species, for convenience, grain-borers. The commonest and 
best known species is Rhizopertha dominica Fab. (fig. 7), and the 
less known species is Dinoderus trancatus Horn. From their differ- 
ent sizes we may call these, for convenience, the lesser grain-borer and 
the larger grain-borer, respectively. The former is cosmopolitan 
and attacks different cereals and several other substances; the latter 
is tropical and though also a general feeder, at least in its adult 
stage, is by virtue of its larger size apparently restricted, in the 
cereals, to maize. 
The former species will receive consideration in the present paper. 
It has already obtained a footing in this country and is frequently 
brought to our shores from outside sources in stored cereals and 
other seeds and similar material, and is of considerable economic 
importance, especially in warm or tropical regions. 
So far as known, it appears to prefer grain to other dry products, 
but shows an inclination to be omnivorous, feeding also upon drugs, 
and boring into the wood of packing boxes and casks. 
Mr. E. C. Cotes has said that this species and the rice weevil " are 
the two insects that do most of the injury to stored wheat in India." 
Owing to its minute size several individuals inhabit even smaller 
seeds. 
No common name, with the exception of " the wood bug," which 
is probably local, appears to have been applied to this insect other 
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