HOW TO KNOW THE INSECS 



Fig. 100. Hydrous trlanp:ularls (Say) 



Black with olive tinge; shining, more so 

 below. In water and flying to lights. 

 Length 54-38 mm. 



The members of this family are supposedly 

 scavengers but there Is good evidence that 

 at least some species catch living Insects 

 or small fish. There are some small spe- 

 cies that live In the dung of cattle and 

 are shaped somewhat like Hlster beetles 

 but may be readily distinguished .from them 

 In not having truncate elytra. 



Figure 100, 



14b Hind legs not modified for swimming 15 



15a Elytra short (a), leaving the greater part of the abdomen 

 exposed. Abdomen flexible with seven or eight segments visible 

 below. (The Rove or Short winged Scavenger *Beetles) Fig. 101. 



Family 16, STAPHYLINIDAE 



Fig. 101. Paederus llttorarlus Grav. 



Head, elytra and tip of abdomen metallic 

 bluish-black; thorax and first four dorsally 

 exposed segments of abdomen yellowish red; legs 

 brownish yellow. Length 4-6 mm. 



This Is a very large family, many species of 

 which are very abundant In decaying organic mat- 

 ter. They have a peculiar way when disturbed of 

 running around with the tip of the abdomen 

 turned up as though threatening to sting. Of 

 /'•^.ck"^ \ course, they have no sting but doubtless earn 

 considerable protection from this ruse. 



Kig;ure 101, 



15b Elytra covering all or at least more than half of the 



abdomen 16 



16a Small oval convex, very shiny beetles with conical tipped 

 abdomen (a) exposed under broadly truncate elytra. Six or 

 seven ventral abdominal segments. (The Shining Fungus Beetles) 

 Fig. 102 Family 20, SCAPHIDIIDAE 



Fig. 102. Scaphldium quadrlguttatum Say 



Shining black with a reddish spot on each 

 elytron. Found in fungi, on which it feeds. 

 Length about 4 mm. 



A variety piceum , wholly black, Is about 

 equally common. The family is a small one. 



Figure 102. 

 * Professor Ralph Voris finds them predacious and not scavengers. 



61 



