COLEOPTERA 491 



by lines of fine punctures and truncate behind, leaving two segments 



of the abdomen exposed (Fig. 578). In some species the wing-covers 



are marked with red. There are nearly four 



\u I hundred described North American species. 



Mf The family LYCID^ includes certain 



'B|\ beetles that were formerly classed in the 



^ ^ fire-fly family; but they differ from the 



Fig. 578. Lampyrid^e in having the middle coxte 



distant, and in that the elytra lack epi- 



pleurae. The elytra are usually furnished with several 



longitudinal ribs and a network of fine elevated lines. 



The members of this family are diurnal in habits; they 



are found on the leaves of plants, where they seek and feed upon 



other insects. A common species is Calopteron reticuldtunt (Fig. 579). 



Family LAMPYRID^ 

 The Firefly Family 



During some warm, moist evening early in our northern June we 

 are startled to see here and there a tiny meteor shoot out of the 

 darkness near at hand, and we suddenly realize that summer is close 

 upon us, heralded by her mysterious messengers, the fireflies. A 

 week or two later these little torch-bearers appear in full force, and 

 the gloom that overhangs marshes and wet meadows, the dusk that 

 shrouds the banks of streams and ponds, the darkness that haunts 

 the borders of forests, are illumined with myriads of flashes as these 

 silent, winged hosts move hither and thither under the cover of the 

 night. 



The fireflies are soft-bodied beetles of medium or small size, with 

 slender, usvially eleven-jointed, saw-like antennae. The prothorax is 

 expanded into a thin projecting margin, which in most cases com- 

 pletely covers the head (Fig. 580). The wing-covers are rather soft, 

 and never strongly embrace the sides of the abdomen, as 

 with most other beetles. 



The fireflies are nocturnal insects and are sluggish by 

 day. The property of emitting light is possessed by adults 

 of both sexes and by larvee. The latter and the wingless 

 females of certain species are known as glow-worms. The 

 light-organs of the winged adults are situated on the lower 

 side of one or more .of the abdominal segments; but they '^^" ^ ^' 

 are lacking in some genera. 



There have been many speculations as to the usefulness of the 

 light-producing power of various organisms to the organisms them- 

 vSelves ; and as regards many of these photogenic creatures no definite 

 conclusions have been reached. But there is considerable evidence to 

 show that in the case of adult lampyrids it serves to enable these 

 insects to find their mates. It has been found that females enclosed 

 in a perforated opaque box do not attract males, while those enclosed 



