PRELIMINARY NOTE ON THE DISTRIBUTION OF 



THE TIGER BEETLES (CICINDELA) AND ITS 



RELATION TO PLANT SUCCESSION. 



V. E. SHELFORD. 



The adult beetles are graceful, predatory, swift-flying insects 

 whose definite distribution and great variability have long been 

 matters of comment. The larvae have been found to be more 

 circumscribed and definite in their distribution than the adults. 

 Our attention has accordingly been turned to the behavior of the 

 larvae and of the adults at the time of egg laying for a possible 

 explanation. 



The egg laying habits are simple. The last four segments of 

 the abdomen are used as an ovipositor. Two pairs of the 

 appendages of these segments serve as digging organs with which 

 small vertical, well-like holes from 7 to 10 mm. deep are made in 

 the soil. A single egg is deposited in a hole and the hole is left 

 uncovered. The tenth segment of the abdomen and one pair of 

 appendages of the ninth segment are covered with hairs which 

 are probably associated with organs sensitive to the varying de- 

 grees of soil moisture and the size of soil particles. The females 

 try the soil before depositing eggs. They make many holes, but 

 lay in only a part of them, and frequently discard them before 

 the usual depth is attained. 



The larvae almost always remain in the spot where the eggs 

 were laid. Upon hatching each larva constructs a burrow in the 

 place of the ovipositor-hole and reconstructs and enlarges the 

 burrow after each moult. If a larva migrates, it almost always 

 selects the same kind of place for digging a new hole as that in 

 which the eggs were laid. 



So much for the general aspects of the life habits. Let us now 

 turn to some examples of distribution and behavior during the 

 egg-laying time. 



The larvae of Cicindela purpurea limbalis are found on steep 



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