. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BIOLOGY OF SOME COMMON 55 conditions at different periods. The largest number hatched on the twenty-sixth day. The newly hatched larvae are not pigmented for a period of a few hours, but they soon resemble the mature larva in shape and appearance, except for their mina- ture size. At this stage they meas- ure about mm. in length. As nearly as could be determined the larvae were in the fourth instar by winter. The first two molts take place rather early in the life of the larva, the first occurring at about t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BIOLOGY OF SOME COMMON 55 conditions at different periods. The largest number hatched on the twenty-sixth day. The newly hatched larvae are not pigmented for a period of a few hours, but they soon resemble the mature larva in shape and appearance, except for their mina- ture size. At this stage they meas- ure about mm. in length. As nearly as could be determined the larvae were in the fourth instar by winter. The first two molts take place rather early in the life of the larva, the first occurring at about the age of two or three weeks. The mature larva (Fig. 7) is elon- gate, rather narrow, varying from 16—19 mm. in length, and it is about three times as long as it is wide. The head is small, a little less than one third as wide as the prothorax, and it can be withdrawn into a pouch within the thorax. The Antennae are three-jointed, the mandibles are arcuate and notched near the middle. The legs are some- what spinose and of nearly uniform length. The body is much flat- tened. The prothorax is rounded on the anterior and lateral sides and subtruncate behind, much the same as in the adult. This is the largest of the body segments. From the metathoraeic segment to the caudal end of the larva the ter- gites are concave posteriorly espec- ially the caudal ones. Each bears a spine on its caudo-lateral margin. The head, mouth-parts and tergites are colored a dark brown, except for a few irregular pale yellowish areas. The dorsal surface is more or less irregularly coarsely punctate. The last segment of the abdomen is provided with numerous retrac-. FIG. 7. Photunis pennsylvanica larva, full grown, dorsal 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 Marine Biological Laboratory (Woods Hole, Mass. ); Marin
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
