LARViE OF INSECTS. 177 



of the ocean. Under the magnifying glass, these masses were 

 found to consist ahuost entirely of the larvae or dried skins of a 

 dipterous insect, adhering together. They had apparently been 

 driven upon the shore at diiferent periods ; some appearing fresher 

 and of a different texture fi'om 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 larvse, which the oars raised at 

 every stroke, rendering the water turbid and offensive. Some of 

 the deposites were very large, and must have covered many hun- 

 dred 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 



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