SOME AQUATIC INSECTS 81 



upside down near the surface of the water, the 

 Beetle buried the hinder part of her body and 

 the two hindermost pairs of legs in the alga, 

 leaving the first pair free, and making use of 

 them to fit and mould the alga to the end of her 

 body. She then began to weave the under side 

 of her cocoon. While the weaving was going on 

 she was careful from time to time to press and 

 flatten the growing cocoon, moulding it with her 

 fore feet against her body, and so giving it the 

 form of a flattened arch. After the first piece, 

 which was intended to form the upper side of the 

 cocoon, was finished, the Beetle turned over and 

 wove another piece, exactly the reverse to the 

 first, to form the under side of the cocoon. The 

 two curved surfaces then were woven together, 

 and the body of the cocoon was finished, the 

 work having occupied about an hour and a 

 quarter. For about two hours after this the 

 Beetle remained still, her back being uppermost. 

 At first her body was buried in the cocoon up to 

 the thorax, but one could now see that she was 

 gradually withdrawing it. During these two 

 hours of her apparent rest she laid her eggs, not 

 at hazard, but in regular order, side by side, the 

 pointed end uppermost. When the work had 

 advanced so far that her body was completely 

 withdrawn from the cocoon, she began to spin 

 about the open mouth of the cocoon, so as to 

 gradually narrow the opening. Then by spinning 

 up and down she closed the end of the cocoon, 

 giving it a truncated appearance. The next 

 thing was to spin a little mast, which gradually 

 rose above the surface of the water, the fore part 



