298 TRANSFORMATIONS OF INSECTS. 



The Gyrinid(Z are water beetles, and are well known by their 

 peculiar habit of describing circles upon the water with wonderful 

 rapidity. This extraordinary movement has given them their 

 scientific name, which infers that they turn round, and we call 

 them popularly Whirligigs, and the French Tourniquets. They 

 are small beetles, the body is oval, and more or less convex, 

 and the feet are perfectly organised for swimming ; the middle 

 and hind ones act as broad oars, and the front legs are used 

 as rudders. They are generally of a very brilliant metallic 

 bronze colour, and when the sun shines on them they look like 

 pearls dancing on the surface of the water. Sometimes they 

 stop short, appear immovable, and look as if they were easy to 

 be caught, when all at once they disappear with the rapidity 

 of lightning, darting about from place to place, whirling round 

 and round, and finally plunging deep into the water. They pass 

 the greater part of their existence on the surface, and watch 

 for their prey below and look out for dangers above. Moreover, 

 they occasionally snap up a passing fly; so Nature has given them 

 four eyes, or rather their eyes on each side are divided, and the 

 insects appear to have two eyes that look upward and two that 

 look downward. When the whirligigs are caught they exude from 

 their body a milky fluid of an extremely strong and disagreeable 

 odour, which remains for a considerable time afterwards. 



The female beetle lays her eggs upon the surface of the leaves 

 of aquatic plants. The adults disappear from the surface of 

 ponds and rivulets when the weather becomes cold, and hide 

 themselves at the bottom, under stones, amongst water weeds, 

 and even in the mud. The larvae are long, very thin, and white, 

 and the hard parts of their bodies are of a yellow tint. The 

 head is small, and all the segments of the abdomen are furnished 

 upon their sides with long ciliated appendages, which act as 

 swimming organs, and also as gills. The last segment has four 

 movable hooks upon it, which enable the insect to jump. The 

 larvai, when full grown, are very active and voracious, and they 

 get out of the way of danger by rapid jumping. About this 

 time they leave the water and take up their abode upon the 

 leaves of aquatic plants, spin a cocoon, and undergo their trans- 

 formations. 



