52 



ZOOLOGY 



another and a well-known family. They are distinguished 

 by soft wing-like elytra and by the great expanse of the 



thoracic shield, which 

 partly or wholly covers 

 the head. Certain non- 

 luminous species live on 

 flowers, especially the 

 golden-rod ; the lumi- 



i 



FIG. 53. Photuris, a firefly. a, larva ; 

 b, adult. The lines to the left of figures 

 represent actual lengths of animals. From 

 Packard. 



nous species are noctur- 

 nal. The light-giving or- 

 gan lies in the abdomen. 

 The larvae also are lumi- 

 nous and are known as 

 glow-worms (Fig. 53). 



A family of consider- 

 able economic import- 

 ance is that of the Tene- 

 brionidae, so called from 



the principal genus Tenebrio, 1 the 



larva of which, known as the meal- 

 worm, occurs in flour and cereals 



and looks much like a wire-worm. 2 



The adult beetle is black and about 



one-half an inch long (Fig. 54). 



The family is not abundant in the 



northeastern part of the United 



States. 



Several kinds of adult beetles 

 be found under the bark of 



can 



FTG. 54. Tenebrio, the meal- 

 worm. Left, larva ; right, 

 adult. From Leunis. 



1 Miller, because it lives in flour. 



2 These larvse are reared by bird-fanciers for bird food, and may be 

 obtained in bird stores. 



