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Show LARVJS OF INSECTS. 177 of the ocean. Under the magnifying glass, these masses were found to consist almost entirely of the larvae or dried skins of a dipterous insect, adhering together. They had apparently been driven upon the shore at different periods; some appearing fresher and of a different texture from others, the insects having been of a larger size. The question where these larvae originated presents a curious subject of inquiry. Nothing living has as yet been detected in the lake, and only a few large insects in the brackish springs, which do not at all resemble these remains either in shape or size. That they have existed in almost incredible numbers is evident, as the shores are lined with their skins, and the bottom, in many instances, for a long distance out from the shores, is covered with them. This is especially the case in the north- east part of the lake, where they lie on the bottom a foot thick, mingled with the oozy mud, of which they form a large proportion. Yesterday I observed from the shore several dark patches far out in the lake, apparently of dull reddish water, looking very much like large shoals. Upon rowing over some of them, however, I found that this change in the colour of the water, here very shallow, was not occasioned by any marked difference in the depth, but from the bottom being covered with these larvae, which the oars raised at every stroke, rendering the water turbid and offensive. Some of the depositee were very large, and must have covered many hundred acres. Monday, May 6.- Morning clear and warm. About a mile to the westward of camp the forces of the land and water party were united, to erect a triangulation station upon a high, rocky knob, near the southern extremity of the* range, commanding a view to the south and west. The distance from the water was about a mile, and the elevation of the station about six hundred feet. Some long sticks were selected from a pile of drift- wood on the beach, and transported on the shoulders of the men, over very rocky, ascending ground, covered with large boulders of a close-grained, compact limestone. The labour was very great, and was much enhanced by the annoyance of swarms of gnats. They have become an intolerable nuisance. Our faces and hands are covered with scars and blotches from the incessant irritation occasioned by their bites. Having erected the station, we proceeded along the shore in search of a camping- place, which was found just south of a little rocky butte, having in front of it the first well- defined reef I had 12 |