124 GYRINI. BRACHELYTixA. 



mon Gyrini (Fig. 399) may be met with, from the first fine 

 days of spring until the end of autumn, on the surface of quiet 

 waters, and even upon that of the sea, often assembled in great 

 numbers, and appearing like brilliant points. They swim with 

 great agility, often curveting in a circular direction, whence 

 their common name. Sometimes they remain stationary with- 

 out the slightest motion ; but no sooner are they approached, 

 than they escape by darting under the surface of the water, and 

 swimming off with the greatest agility. The four hind-legs are 

 used as oars, and the anterior pair for seizing the food, which 

 appears to consist of the dead bodies of insects and other small 

 aquatic animals. When they dart beneath the surface, a bubble 

 of air, like a silvery ball, remains attached to the hind part of 

 the body. The larva is long and slender, and each side of the 

 body bears a series of fringed filaments, which are evidently 

 respiratory organs. The larva undergoes its change to the 

 pupa state in the interior of a small cocoon, which it attaches 

 to the stem of some aquatic plant above the surface of the water. 

 705. The next tribe of the Pentamerous Beetles is that of 

 BRACHELYTRA, distinguished, as the name imports, by the short- 

 ness of the elytra. They have only four palpi. These insects 

 run and fly with equal agility ; they are ex- 

 tremely voracious, not only feeding on living 

 prey, but also deriving their nutriment from dead 

 and decaying animal and vegetable matters. The 

 majority live in the earth, amidst manure and 

 putrescent substances ; others are found among 

 Fungi and rotten wood, and under stones ; others, 

 again, are only met with near water ; and a few 

 of the smallest are only found in flowers. The 

 - larvae feed on the same substances, and in the 

 same situations, as the perfect insects ; and 

 greatly resemble them in form. These Beetles, of which one 

 of the largest is frequently to be seen running about garden- 

 walks, and is commonly known under the name of the Devil's 

 Coach-horse, turn up the end of the body when touched, 

 bendjng it in all directions ; and they possess the power of emit- 



