. Bulletin of the Department of Agriculture. Agriculture. 10 BULLETIN" 766, U. S. DEPARTMENT OF AGRICULTURE. halfway down the posterior uterus, causing this organ to resemble a flat, more or less coiled ribbon, gradually enlarging toward the external organs of reproduction. As the developing larvse are forced downward their axes gradually change until the axis of the posterior uterus and the larvse is the same. (Fig. 4.) At the distal termination of the posterior uterus is the "laying organ " or larvipositor. This is slightly chitinized and has a small tubelike opening just
. Bulletin of the Department of Agriculture. Agriculture. 10 BULLETIN" 766, U. S. DEPARTMENT OF AGRICULTURE. halfway down the posterior uterus, causing this organ to resemble a flat, more or less coiled ribbon, gradually enlarging toward the external organs of reproduction. As the developing larvse are forced downward their axes gradually change until the axis of the posterior uterus and the larvse is the same. (Fig. 4.) At the distal termination of the posterior uterus is the "laying organ " or larvipositor. This is slightly chitinized and has a small tubelike opening just large enough for the passage of one larva. This organ, as well as the anus, arises in the venter of the sixth abdominal segment and is curved forward when at rest, fitting into the carinate venter of the fifth abdominal segment. The larvipositor fits into a curved chiti- nous hook or piercer, which is grooved, re- resembling a V in structure. Beneath this hook is a supporting organ arising from the fifth segment, which is strongly spined on both sides in such a manner that it reinforces the piercer while the female is in the act of attacking the host caterpil- lar. The parasite larva?, as they are I . forced down the posterior uterus, are â turned in some manner and are injected into the host, with the anterior end first. This was the conclusion the writer reached after making a number of dis- sections of females after they had de- posited part of their young. In these dis- sections some of the larvae were found to be inclosed in a very thin membranous sheath, which fitted the body very closely, while others were found naked. This leads to the inference that Compsilura deposits both bare and inclosed larvse. Pantel suggests that this might be possible on account of a prolon- gation of the egg stage, due to the absence of an appropriate host. DISCUSSION OF LARVA STAGE OF COMPSILURA CONCINNATA. Compsilura larva? pass their entire life within the body of the host. The young larv
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