It is to the Hymenoptera that the student must look for the most varied and interesting phases of insect life. Here he finds numerous avocations conducted with much intelligence, and in many families sees strong social instincts developed. It is not, however, of these latter that I intend now to speak, but of a few solitary ones. Even those just entered upon the study of insect life must be fully aware of the continual destruction of our fruit and timber trees, both alive and in process of manufacture, by the boring, wood-eating larvæ of various insects.