HOW TO KNOW THE INSECS 



8b Varying much in form and size, but not as in 8a. (Ground 

 beetles) Fig. 90.* Family 2, CARABIDAE 



/^^ 



Fisrure 90. 



Fig. 90. Agonoderus coirjna (Fab.) 



Yellowish bro\^/n with wide black stripe on 

 each elytron. Antennae reddish brovm, legs 

 pale. One of our most common Iowa beetles: 

 Often very abundant at lights. Length 5-6 

 mm.. 



Ground beetles are for the most part 

 active only by night. During the day they 

 hide under stones and debris. A great many 

 species m.ay be taken, especially in the 

 spring, by looking under boards and stones 

 lying on the ground. Black is the most 

 usual color but many are beautifully marked, 

 They range widely in size, and are bene- 

 ficial in killing other insects. 



;eje? 



Fi •J re 



9a Two pair of eyes, one pair on upper surface and one on 



lower surface of head. Antennae very short. CWhi rl igig Beetles) 

 Fig. 91. Family 7, GYRINIDAE 



Fig. 91. Dineutes americanus Say 



Black vath metallic luster; legs 

 brovmish yellow. Often seen in 

 large numbers on surface of quiet 

 water. Known as "apple-bug" or 

 "penny-bug" on account of scent. 

 Length 10-12 mm. 



Whirligig beetles are well kno¥/n, 

 although the family is not large. 

 The collector will find it good 

 sport to attempt catching them. 

 They seldom dive but are good at 

 dodging. 



9b One pair of eyes. Antennae eleven |ointed; slender. Hind 

 legs with fringes of long hairs and large spurs. (The Pre- 

 dacious Diving Beetles). Fig. 92. Family 6, DYTISCIDAE 



Fig. 92. Agabus disintegratus (Cr.) 



Head and thorax dull reddish; elytra dull 

 yellow; markings black. Length 7-8 mm.. 



Some members of this family are large 

 beetles, averaging over an inch in length. The 

 larvae, which live in water also, are known 

 as vrater tigers and are highly destructive to 

 fish fry and other sm.all anim.als with which 

 th^y are associated. These beetles fly 

 readily and are often taken at lights. 



* A few pround beetles have the head vdder than the thorax 

 and might seem to be tiger beetles. The f,enus Ela phrus , oon- 

 Figure S2. men on mud flats with E:bout 20 North American species, is one 

 of such. They differ from the tiger beetles by the antennae 

 : rininp "t side, of head between base of nandible and the eye instead of on the front 

 cf head above the base of the mandible. 



58 



