Annual report of the North Carolina Agricultural Experiment Station . entyears some authorities have claimed that this species is predaceousand carnivorous rather than granivorous, but the writer has observedthat it possesses both habits. Chittenden states that he has proved itto be both a feeder on grain and other insects. Consequently thecadelle represents an insect that is both beneficial and injurious. Inold corn it is particularly destructive, and in my opinion the injury 12 N. C. AGRICULTURAL EXPERIMENT STATION. caused is greater than its beneficial work by destroying other graininsects.
Annual report of the North Carolina Agricultural Experiment Station . entyears some authorities have claimed that this species is predaceousand carnivorous rather than granivorous, but the writer has observedthat it possesses both habits. Chittenden states that he has proved itto be both a feeder on grain and other insects. Consequently thecadelle represents an insect that is both beneficial and injurious. Inold corn it is particularly destructive, and in my opinion the injury 12 N. C. AGRICULTURAL EXPERIMENT STATION. caused is greater than its beneficial work by destroying other graininsects. It is not uncommon to find cadelle larvae feeding in grainfrom which weevils have emerged. The parent beetle (Fig. 5) is elongate, flattened, and nearly black,measuring about one-third of an inch in length. The larva (Fig. 5)measures nearly three-fourths of an inch when fully grown, its generalcoloring being whitish, with the head and anal segments dark brown,and the three thoracic segments marked with brown. The body isfleshy and tapers gradually toward the FlG. 5.—The Cadelle; full-grown larva? twice natural size; parent beetle seventimes natural size. Both the larva and adult feed in the grain, frequently changingtheir positions, perhaps in search of weevil larvae, but most assuredlythey cause much injury and should be dealt with like any other graininsect. Only one generation is produced annually, which is very fortunate,as otherwise the species might prove one of our worst grain experiments by the writer have shown that the beetles are moredifficult to kill by fumigation with carbon bisulphide than the adultcorn weevil, although the larvae are quite readily destroyed by thistreatment. CORN WEEVILS AND OTHER GRAIN INSECTS. 13 The Saw-tooth Grain Beetle (Silvanus surinamensis, Linn). This is one of the smallest, but most common, of the insects attack-ing grain and nearly all food stuffs. Its small size enables it to pene-trate the smallest cracks, an
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