60 OUTLINES OF ENTOMOLOGY. 



indeed the entire surface, minutely roughened and indented as it is, ap- 

 pears like beaten metal. The head is deeply sunken into the thorax, 

 and the latter widens slightly behind and fits tightly over the base of 

 the wing covers. 



The Buprestians are diurnal insects, flying in the sunshine or 

 basking in it while slowly crawling up and down the trunks of trees, in 

 the bark of which they deposit their eggs. The larvie are wood-borers, 

 ^all-makers or leaf-miners, and are all more or less destructive to forest 

 and fruit trees and shrubbery. They are characterized by a relatively 

 enormous expansion of the pro-thoracic joint, from which the remain- 

 ing two joints of the thorax taper abruptly to the slender, cylindrical 

 abdominal division. There are no legs, and the enlarged joint has a 

 smooth horny plate on both upper and under sides, and is much flat- 

 tened. 



The well-known Flat-headed borer fChysohotlirds femorata, Fabr.), 

 so destructive to many kinds of fruit and shade trees, is the best repre- 

 sentative of the boring species. The species of Agrilus cause swellings 

 in the stems of blackberries and raspberries. These beetles are slender 

 and cylindrical, with dark-blue or black wing covers and copper-colored 

 thorax, and are about one-fourth of an inch long. The larvae of the 

 species, included in the genus Brachys, mine the leaves of apple and 

 oak. 



The Fire-flies and Soldier beetles are very different in many re- 

 spects from the preceding group. Their bodies are very soft and the 

 wing covers thin and flexible. In the "Fire-flies" or "Lightning-bugs" 

 { genera Photinus and Photurus), the head is almost concealed under 

 the expanded margin of the pro-thorax. The light which they emit is 

 supposed to be from a phosphorescent substance in the abdomen, and 

 is given off in flashes at irregular intervals, both during flight and re- 

 pose. In Photinus pyralis both sexes are winged and luminous. In 

 Photurus, the somewhat smaller and less brilliant species often have 

 wingless females. 



The larvae, which are " glow-worms," burrow in th eearth, often com- 

 ing to the surface, and have a faint luminosity. They feed on the soft 

 larvae of other insects and on earth-worms. 



The most common species of Soldier-beetle is a slender, clay-yel- 

 low insect, with a large black spot on the top of the pro-thorax and an 

 oblong one near the tip of each wing cover. This beetle bears the 

 rather formidable name of Ghauliognatlms pennsylv aniens, De G. The 

 larvae somewhat resemble those of the lady-birds and like them are of 

 service to us by feeding on other insects that are injurious to vegeta 

 tion. The beetles may almost always be found in the autumn upon the 

 flowers of the Grolden-rod and Eupatorium. 



