THE INSECT WORLD. 



191 



flies " are first noticed in June in the more northern and central 

 portions of the United States, and have the terminal segments 

 of the abdomen on the under side of a bright sulphur-yellow 

 color, which at the will of the insect glows with a phosphorescent 

 light of considerable illuminating power. They hide during the 

 day on the foliage of plants or in crevices, and begin their flight 

 with the deepening of the twilight. In some species the female 

 is without wings and remains on the ground among the grass — 

 the "glow-worm." The larvae are predaceous, and some of 

 them live on snails. 



Belonging to the same family, but of a diurnal habit and with- 

 out the illuminating power, are the "soldier-beetles," belonging 

 to the genera Chauliogna- 

 thus and Telephorus, dis- 

 tinguished also by having 

 a more prominent head 

 and large, round eyes. 

 These may be found on 

 flowers, where they prob- 

 ably feed on pollen, but 

 are of direct benefit by 

 aiding in pollination. The 

 lar\-ae are even more de- 

 cidedly useful, being predaceous and feeding largely on soft- 

 bodied grubs and the like. They are long and slender, flattened 

 above and somewhat narrowed at each end, or fusiform, the 

 edges of the segments quite prominently marked. They are 

 especially effective against such creatures as the larvse of the plum 

 curculio when they enter the ground to pupate, and a large pro- 

 portion are thus disposed of annually. 



The species belonging to the family MalachiidcB resemble the 

 Lampyrids in the soft body texture and leathery wing- covers, 

 but they are much shorter and broader, the broadest part of the 

 body coming near the end of the wing-covers. The antennae 

 are short, a little enlarged at the tip, and often curiously 

 knotted in the male. Many of the species have soft, orange- 

 colored vesicles, capable of being protruded from the side of 

 the body. They are usually found on flowers and feed on other 

 insects or insect eggs, probably doing much good in this way. 



Fig. 176. 



Soldier-beetle, Chauliognathus pennsylvanicus. 

 —a, larva; b, its head enlarged; c to h, struc- 

 tural details ; i, beetle, natural size. 



