THE PERFORATION OF FLOWERS.
The subject of the relations and adaptations which exist between flowers and insects does not appear to excite as much popular attention as many other branches of natural science which are no more interesting. Sprengel, Darwin, and Hermann Muller have been the chief authors in giving us our present knowledge and interest in the study; Sir John Lubbock has helped to popularize it, and Prof. W. Trelease and others have carried on the work in this country.
The perforation as well as the fertilization of flowers has received attention, but there is a wide field for further study for those who have leisure to pursue it, as it requires much time and patience, as well as closeness and accuracy of observation.
The accompanying figures, from drawings by Mr. C.E. Faxon, show a few characteristic perforations and mutilations, and also represent two of the principal kinds of insects which make them.
Any one interested in the subject will find an excellent brief review of the work already done, a fair bibliography, and a list of perforated flowers in Professor L.H. Pammel's paper on the "Perforation of Flowers," in the Transactions of the St. Louis Academy of Science, vol. v., pp. 246-277.
The general beauty of flowers is usually not greatly marred by the perforations except in a few cases, as when the spurs of columbines and corollas of trumpet creepers are much torn, which frequently happens.
The great object of the perforations by insects is the obtaining of the concealed nectar in an easy way. Very naturally, flowers which depend on insect agency for fertilization rarely produce seed when punctured if they are not also entered in the normal way. Perforating is only practiced by a small number of species of insects, and many but not all of the perforators do so because their tongues are too short to reach the nectar by entering the flower. Some obtain nectar from the same kind of flower both in the normal way and by perforating.
The chief perforators of flowers, in this part of the continent at least, appear to be some kinds of humble bees (Bombus) and carpenter bees (Xylocopa). These insects have developed an unerring instinct as to the proper point to perforate the corollas from the outside, in order to readily get at the nectar. The holes made by the humble bees and by the carpenter bees are usually quite different and easily distinguished.