. Butterflies worth knowing. Butterflies. 42 BUTTERFLIES gradually growing larger and larger until at last it reaches a length of possibly an inch. By this time it is likely to have absorbed so large a part of the inside of the cater- pillar that the latter dies. The parasite larva now changes to a pupa, either inside or outside the skin of the cater- pillar, and a little later changes again to an adult Ichneu- mon fly. In the case just given, one egg only was deposited within the skin of the caterpillar. In many others, however, a large number of eggs may be so deposited by a single fly, A sp
. Butterflies worth knowing. Butterflies. 42 BUTTERFLIES gradually growing larger and larger until at last it reaches a length of possibly an inch. By this time it is likely to have absorbed so large a part of the inside of the cater- pillar that the latter dies. The parasite larva now changes to a pupa, either inside or outside the skin of the cater- pillar, and a little later changes again to an adult Ichneu- mon fly. In the case just given, one egg only was deposited within the skin of the caterpillar. In many others, however, a large number of eggs may be so deposited by a single fly, A special group of Ichneumon flies, called the Microgast^ ers, contains many parasites that have this peculiarity. The Microgaster larvae on coming forth from the cater- pillar have the habit of spin- ning tiny cocoons within Tachinla Parasite; a fly; S. pupanum. which thcV chanSJC tO pUpaC. magnified ^^ cj a x By collecting some cabbage worms which are nearly full grown, and keeping them in a glass jar one can generally get a considerable number of these Microgaster cocoons and rear the flies from them. Another group of caterpillar parasites is still more mi- nute. They are called the Chalcid flies. Their life-his- tories are full of interest, and might easily furnish oppor- tunity for a long lifetime of study and experiment. One is likely to get hundreds of these Chalcid flies from a single caterpillar. Another interesting group of parasites is that of the two-winged Tachina flies (see cut on this page). The life- story of some of these is comparatively simple: a buzzing. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Weed, Clarence Moores, 1864-1947. [Garden City, N. Y. ] Pub. by Doubleday, Page & Company for Nelson Doubleday
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbutterf, bookyear1923
