Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomol00smit Year: 1906 THE INSECT WORLD. 589 increase come in is not entirely clear in all cases. Take, for instance, the cabbage butterfly already spoken of. I have, in collecting' chrysalids in spring, found scarcely one in twenty that was living, and from which I obtained a butterfly. All the others produced parasites, chiefly the little Chalcidid already spoken of: hundreds of them for every butterfly ! It would seem, then,
Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomol00smit Year: 1906 THE INSECT WORLD. 589 increase come in is not entirely clear in all cases. Take, for instance, the cabbage butterfly already spoken of. I have, in collecting' chrysalids in spring, found scarcely one in twenty that was living, and from which I obtained a butterfly. All the others produced parasites, chiefly the little Chalcidid already spoken of: hundreds of them for every butterfly ! It would seem, then, as if there were parasites enough here to attack every caterpillar that hatched from the eggs of this first brood ; yet somehow they seem to be almost entirely free, and the butterflies increase normally until after midsummer. It seems almost impossible, in fact, to get a parasitized larva until August or September, and not until we get the last brood of caterpillars do the parasites seem to resume activity, after all the injury has been done to the cabbage crop. Perhaps ninety per cent, of all the caterpillars will be found infested at this time, and a mere fragment of the brood comes to maturity the following spring. We are unfamiliar with the complete life history of most of these little species, and, indeed, a great many yet remain to be described. It would be rash to say that we can never use them for our own purpose,—that is, in checking injurious species ; but if so, it is certain that we must know very much more about them than we do at present. A very curious creature sometimes found flying through open woods is the Pelecinus polyturator, for which the family Peleciii- idcE has been established. The female is remarkable for the length of its slender abdo- men, each of the joints Fig. 448. being almost as long as the head and body, and the entire insect is sometimes nearly four inches in length, the abdomen alone measuring more than three. The insect is so very odd an
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