. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. , THE LARGER GRAIN-BOREE. 51 insect might have an opportunity to escape from confinement. A number of adults, 14 in all, were placed, on June 21, in a rearing jar containing an ear of corn. At the end of two months the ear, includ- ing the cob, was fully half destroyed, and later the bored ear was converted into dust and other debris. A similar number of beetles was confined in a rearing jar with shelled corn, June 25. Late in the afternoon and the following morning three kernels of corn were found to have been e
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. , THE LARGER GRAIN-BOREE. 51 insect might have an opportunity to escape from confinement. A number of adults, 14 in all, were placed, on June 21, in a rearing jar containing an ear of corn. At the end of two months the ear, includ- ing the cob, was fully half destroyed, and later the bored ear was converted into dust and other debris. A similar number of beetles was confined in a rearing jar with shelled corn, June 25. Late in the afternoon and the following morning three kernels of corn were found to have been entered, two having been bored entirely through. Figure 10 shows the work of the beetle in a kernel of corn. These experiments show the rapidity with which the adults work, as also partiality for corn in the ear, the insect scarcely being at home in shelled corn, while in other material with which it was fed in other experiments the insect did not breed at all. There seems little doubt that the grain-feeding habit of this species is an acquired one of comparativeh' recent times, and that it normally, or under natural conditions, breeds in roots and tubers. During the course of these experiments it was ascertained that the pupal stage varied from about four and one-half days in the very hottest weather to six days in a little cooler weather during June and JuW, while in October the pupal period lasted twelve days, from October 17 to 29. The egg was not ob- served, but the e^P; period is with little doubt about ^'^; io-K<^'-»ei ' fefe i _ of corn showing the same as for the pupa under the same atmospheric work of beetle conditions. By experiment it was learned that the hlrev^Toinmie- entire life cycle from the placing of beetles in corn ms tmncatus). until the issuance of the new generation, i. e., from K)i-i''rnaiV August 25 to October 9, was forty-five days, or about six and one-half weeks. The temperature was moderately warm during this period. Still another experiment was
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