CRAYFISHES OF THE GENUS CAMBARUS IN NEBRASKA 
AND EASTERN COLORADO 
& 
By EARL THERON ENGLE 
Department of Anatomy, Stanford University 
CONTENTS 
Page 
Introduction 87 
Methods 88 
Acknowledgements 88 
Description of species, with key to sub- 
genera and species 88 
Key to the species 89 
Cambarus (Cambarus) simulans 
Faxon _ 90 
Cambarus (Faxonius) propinquus 
Girard 90 
Cambarus (Faxonius) virilis Hagen_ 91 
Cambarus (Faxonius) immunis 
Hagen 91 
Cambarus (Faxonius) immunis spin- 
irostris Faxon 92 
Page 
Description of species, with key to sub- 
genera and species — Continued. 
Cambarus (Faxonius) neglectus 
Faxon 92 
Cambarus (Bartonius) diogenes 
Girard 92 
Cambarus (Bartonius) argillicola 
Faxon 93 
Geographical distribution 93 
Ecology and life histories 95 
Parasites 98 
Economic importance 99 
Summary 101 
Bibliography 101 
INTRODUCTION 
The morphology of the crayfish has been studied in most elementary courses 
of zoology since the inception of the type method of study with Huxley’s Anatomy 
of Invertebrated Animals in 1877. Previous to this (in 1878) Huxley had pub- 
lished a comprehensive treatise on the classification and distribution of the cray- 
fish. Field observations in the United States began as early as 1852, when Girard 
investigated the habits of certain species and did some preliminary work on the 
geographical distribution of the family Astacidse. This type of field observation 
was soon replaced by the taxonomic work of many writers, which resulted in the 
monographs of Hagen (1870) and Faxon (1885a) and in the numerous State surveys, 
of which the earliest were those of Forbes (1876) for Illinois, Bundy (1877) for 
Wisconsin, Herrick (1S82) for Minnesota, and Hay (1896) for Indiana. With the 
exception of the crayfish surveys for Missouri (Steele, 1902) and Kansas (Faxon, 
1885b; Harris, 1900), no work has been done up to this time within the States of 
the Missouri River drainage system. 
In addition to the numerous studies on the taxonomy and geographical distri- 
bution of crayfishes, much work has been done in physiological experimentation with 
these animals. Powers (1914), Bell (1906 and 1906a), and others have used -various 
species of crayfishes in experimental work, and others will doubtless use them for 
ecological investigation. They are very hardy and more easily kept in the labora- 
87 
