i44 THE STUDY OF INSECTS 



ments; this abdominal band is best marked on the lower side of the 

 body. 



Staphylinus maculosus is a larger species, which often measures fully 

 an inch in length. It is densely punctured, and of a dull brown color, 

 with the scutellum black, and a row of obscure, square, blackish spots 

 along the middle of the abdomen. 



Staph yllii us vulpinus resembles the preceding somewhat, but it has a 

 pair of bright yellow spots at the base of each abdominal segment. 



Ontholestes cingulatus is of about the same size as the preceding. It 

 is brown, speckled with brownish-black spots, and the tip of its abdomen 

 is clothed with golden hairs. 



Family Lampyrid^e 



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 over- 

 hangs 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, usually eleven-jointed, saw-like antennae. The prothorax is 

 expanded into a thin projecting margin, which in most cases 

 completely covers the head (Fig. 243). The wing-covers are 

 rather soft, and never strongly embrace the sides of the abdo- 

 men, as with most other beetles. 



The fireflies are nocturnal insects and are sluggish by day. 



fig" 243. The property of emitting light is possessed by adults of both 



sexes and by larvae. 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 themselves; 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 in a glass vial do; thus 

 showing that it is the light emitted by the female, and not its odor, that 

 attracts the male. It has also been shown that in some cases at least 

 there are specific differences in the method of flashing which enables the 

 insects to distinguish at a distance their proper mates. 



