32 



not improve they die. The majority never get beyond the larval 

 stage. 



The adults run and fly swiftly, being able to catch the swiftest 

 insects. \\'hen disturbed, they run rapidly away, stopping suddenly. 

 If pressed, they take wing, flying low and stopping suddenly as be- 

 fore. It takes a trained eye to follow their movements. The adults 

 of most of the species are terricolous, always being found on bare 

 ground. They take shelter during the night in holes dug in the 

 sand, under bark, stones, etc. 



The western and southwestern parts of North America present 

 optimum conditions for the development of the Cicindclidae, and 

 there they are most abundant and varied, though many species are 

 widely distributed. The tiger-beetles are also well represented on 

 other continents. 



The peculiar preference of the females for certain kinds of soil 

 for egg-laying results in rigid habitat restrictions. The most com- 

 mon habitats are sandy roads and fields; shores of rivers, lakes, and 

 the ocean; mud flats; and bare rock or clay exposures. The beetles 

 are found in habitats usually occurring only locally ; hence their geo- 

 graphic distribution, though extensive, is discontinuous. 



Bombyliid flies parasitize the larvs of certain species ; a few 

 birds may be rapid enough to capture the beetles ; and the lizard 

 Cneniidophorus scxlineatus is reported to catch and eat them. The 

 larvje, being sedentary, are much more subject to attack, and many 

 kinds of predaceous animals doubtless eat them. It is probable that 

 physical conditions are the greatest natural check, rather than pre- 

 daceous or parasitic animals. 



The Cicindelidac are dominant forms among insects. They are 

 characteristic of open formations, usually where the ecological in- 

 fluence of vegetation is subordinate to physical conditions of the 

 environment. In the sand prairie three species represent the group, 

 four others being occasionally present. Physical conditions of sand 

 prairie are nearly the optimum for the development of tiger-beetles; 

 they are therefore much more characteristic of this formation and 

 form a more important part of it, than of more luxuriant forma- 

 tions, as the black-soil prairie or the deciduous forest. In the sand 

 prairie the Cicindclidae are probably more important than the Corab- 

 idac, by which they are overwhelmingly suljordinated in black-soil 

 prairie. 



Cicindcla fonnosa gcncrosa Dej. June 25, July 12, 16, 22, October 6. 



This large species lays eggs in May and June. A generation 



lives two years, as described in the generic discussion. The burrow. 



