HOW TO KNOW THE INSECS 



2a Hind tarsi with the same number of segments as the 



fore tarsi 3 



2b Hind tarsi with only four segments. Fore tarsi with' 



five segments 33 



3a All tarsi with five segments. (If 



the 4th segment is obscure as in Flo. C^^'"'"''^ ta.rsu6 



83a, take 3b). Fig. 82 ".4 ^^ -~I : ^ ^^ fe fe:jbe^ 



Fig. 82 Middle leg of ground beetle. ^^^^^^^£3^J 



Figure b2 



3b All tarsi with apparently four 

 segments. Fig. 83 42 



Figure 83. 



3c All tarsi with apparently three 

 segments. Fig. 84 47 



Fip-ure 84. 



4a Antenna almost always fili- 

 form.* (a) (In family Gyrinidae 

 the antennae are very short and 

 modified as in Fig. 85b). First 

 ventral segment of abdomen com- 

 pletely divided by hind coxal 

 cavities, (c) Fig. 85 [ 



FiOTre 85, 



4b Antenna* of various shapes, usually not 

 filiform.* (See Fig, 29). First ventral 

 segment all in one piece and not cut 

 entirely across by the hind coxal cavi- 

 ties. Fig. 85-^ 10 



5a Legs fitted for walking or running. . 6 



5b Aquatic beetles with legs fitted for 

 swimming, usually by being flattened 

 and fringed with stiff hairs. Fig, 86. 9 



Figur 



If the antennae are filiform the first ventral segment should almiys be examined. 



56 



