BY W. R. COLLEDGE. 118 



mistake is never made in putting an egg wrong end downwards. 

 All are placed with the thick end on the water. The consequence 

 is that, being conical, when they are all massed closely together, 

 each egq slopes to the centre, producing that curbed boat-like 

 shape you see in the lower part of the picture. 



The upper figure represents an egg-boat turned up on end. 

 You are looking at it inside. The eggs are placed so closely 

 together that it looks like one dark mass. Counting the rows in 

 the first boat they will be found to be about twenty-five. And 

 if you take an average of ten eggs in the breadth, these numbers 

 if multiplied will give you 250 in the boat. That is a fair 

 average. Some contain 800, others less. It forms a thoroughly 

 good and perfectly unsinkable lifo raft. Push it down into the 

 water ; it springs up again lighter than cork. The mosquito- 

 boat is so perfectly built that it is impossible for it not to right 

 itself when it has been submerged. If you try the experiment 

 of pouring water from a jug down on it from a height you will 

 find, though it may be driven down into the water and whirled 

 about in all directions, you cannot break it up, and as soon as it 

 is free it will rise to the surface and right itself perfectly. I 

 have seen a dozen of these little vessels lying side by side just 

 like a little fleet of boats. 



The mother has now done her work and she leaves it, like 

 Moses in the ark of bulrushes, to the tender mercies of the 

 elements. The warm, moist air assumes the functions of the 

 mother, and in from 1^ to 3 days the young are hatched. 



In the first picture I mentioned that there was a little 

 projection in the centre of the large round end of the eo-o-. 

 This is a detachable cap which, apparently, has not been hitherto 

 remarked by observers, so that our society has the honour of 

 adding this interesting fact to the world's book of science. It 

 is very minute, almost transparent, and in that state difficult to 

 photograph. Some little time ago, however, I managed to fix 

 these caps on a slide and strain them. One specimen I sent to 

 Dr. John Thompson, and he gave me a surprise by returnino' in 

 a couple of days a most admirable lantern slide enlargement of 

 it. It is one of the most perfect micro-photographs that I have 

 ever seen. A copy of it is seen in figure 2. It bears a 

 resemblance to one of those pretty little table mats, with a deep 

 fringe with which young housewives so often decorate their 



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