Museum, University of Nebraska State


Date of this Version

June 1917


Contributions from the Zoological Laboratory of the University of Illinois, No. 93


In 1903 the writer undertook a study of variation of the tiger beetles. The work here presented is the outgrowth of this beginning, and indeed includes some small portions regarding color patterns that were written in that year. The work has been prolonged for many reasons, but chief of these was the very large number of species in the group and the fact that an adequate understanding of the material could not be attained without consulting many large collections. Further, the experimental results obtained in 1906 demanded a firsthand study of the variations of the species concerned and their natural habitats. The accumulation of material and data was not completed until 1911. Some of this had to be studied, drawings made, etc., which with numerous other duties and enterprises under way made necessary much time to put it into the present form.

A family with upwards of 1300 species of which more than 600 are in one genus and with characters which can be studied and analyzed, appeared to afford material which was sufficiently promising to justify delay. In the fourteen years that have elapsed since the problem was first undertaken at the suggestion of Dr. C. B. Davenport, the attention of biologists has shifted from variation, which was then the chief topic of interest, to experimental modification of characters, and finally to the methods of modern genetics. Various men have made numerous suggestions regarding the work, but in its final preparation the writer has been able to use only a few of them in a general way, and an attempt is made to present the facts and conclusions growing out of the material as simply as possible.

With Twenty-Nine Black and Three Colored Plates

Materials and methods
Analysis of Color Patterns
Color Patterns and Elytral Structures
The Color Pattern Plan
Color Pattern and Pigment Development
Experimental Modification of Patterns
Geographic Variation of Patterns
Colors of Tiger Beetles
Causes of Colors
Ontogeny of Color
Relation of Ontogenetic Stages to Geographic Races
Geographic Variation in Color
Experimental Modification of Color
Relation of Colors and Color Patterns to Climate
Geographic Center of the Group on the B'asis of Patterns
General Discussion
Pattern Tendencies
Bearing of the Color Pattern Mechanism on Orthogenesis
Bearing of the Pattern Mechanism on the Biogenetic Law
Summary of Conclusions
Explanation of Plates

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