3 I2 



ELEMENTARY ENTOMOLOGY 



C. Tarsi consisting of five segments . . . Section PENTAMERA 

 D. Antennae filiform, with distinct cylindrical segments. 



Tribe ADEPHAGA 

 E. Legs adapted for swimming, aquatic in habits. 



F. Eyes divided laterally, making apparently four compound 

 eyes. Whirligig-beetles. (Page 140) . . GYRINIDAE 

 FF. Eyes not divided. Predacious diving-beetles. DYTISCIDAE 

 EE. Legs adapted for running ; terrestrial in habit. 



F. Antennae inserted on front of head above base of man- 

 dibles. Tiger beetles. (Page 137) . CICINDELIDAE 

 FF. Antennae inserted on sides of head between base of 

 mandibles and eyes. Predacious ground-beetles. (Page 



138) CARABIDAE 



DD. Antennae not filiform. 



E. Antennae capitate or clavate . . . Tribe CLAVICORNIA 

 F. Aquatic, legs fitted for swimming. Water-scavenger 



beetles. (Page 141) HYDROPHILIDAE 



FF. Terrestrial, legs not fitted for swimming. 



G. Antennae moniliform, the segments gradually en- 

 larging toward the end ; elytra covering only basal 

 half of abdomen. Rove-beetles . STAPHYLINIDAE 

 GG. Antennae of various forms (clavate or capitate) ; 



elytra covering most of abdomen. 

 H. Abdomen with six or more ventral segments ; an- 

 terior coxae conical ; antennae gradually thickened 

 or clavate. Carrion-beetles. (Page 142) 



SILPHIDAE 



HH. Abdomen with five ventral segments j anterior 

 coxae conical and projecting from the coxal cavi- 

 ties ; last three segments of the antennae forming 

 a large club. Larder-beetles, etc. DERMESTIDAE 

 EE. Antennae serraf or laflirffete, 



F. Antennae serrated. Saw-horned beetles. (Page 144) 



Tribe SERRICORNIA 

 G. Head inserted in thorax, which extends as far as 



compound eyes ; body elongated or elliptical. 

 H. First two abdominal segments fused together on 

 ventral side. Metallic wood-borers. (Page 146) 



BUPRESTIDAE 



HH. First two abdominal segments not fused. Click- 

 beetles. (Page 144) . . . . ELATERIDAE 

 GG. Head not inserted in thorax as far as compound eyes. 

 H. Head bent nearly at right angles to thorax, which 

 protrudes over it. Size usually less than one 

 fourth of an inch . PTINIDAE 



