COCOON-MAKING. 93 



one. The female Beetle is furnished with a complete 

 silk-spinning apparatus, the spinnerets being placed, 

 not in the mouth, as is the case with the silkworm, 

 but at the end of the tail. With these instruments 

 she forms a cocoon shaped almost exactly like a 

 turnip, being round, and having a pointed projection 

 from one side. Within this cocoon, which soon 

 becomes hard and water-tight, and is fastened to the 

 stem of a water-plant, the eggs are placed ; and in a 

 time varying from a fortnight to six weeks, according 

 to the warmth of the weather, the larvae are hatched. 

 About fifty or sixty eggs are placed in one cocoon, 

 and by this extraordinary provision they are pre- 

 served from harm until the larvae are able to escape 

 into the water and shift for themselves. They are 

 very small at first, but rapidly increase in size until 

 they attain the length of three inches. 



The larva is soft, fat, and dusky in colour, and 

 feeds voraciously on molluscs and other aquatic 

 animals, as might be inferred from the large and 

 curved jaws. It is one of the air-breathing larvae, 

 and is therefore obliged to come frequently to the 

 surface in order to take in a supply of air, which is 

 done by means of a filamentous appendage at the 

 end of the tail. Somewhere about July the larva has 

 completed feeding ; and then leaves the water and 

 crawls up the bank, searching for a soft spot in which 

 to burrow. Here it sinks its tunnel, and forms an 

 oval cocoon, in which it awaits its change into the 

 pupal state. 



The Beetles belonging to this group, being, like 

 the larvae, air-breathers, are forced to come to the 



