217] STUDIES ON GREGARINES —WATSON 



INTRODUCTION 



The following pages contain results from the study of a number of 

 species of gregariues found as parasites in various Orthoptera, Coleop- 

 tera, and Myriapoda during the past three years. The work was done 

 chiefly in the zoological research laboratory of the University of Illinois, 

 under the supervision of Professor Henry B. Ward. I am deeply in- 

 debted to Professor Ward for his direction and helpful suggestions 

 throughout. Four of the species described were found and studied at 

 the Biological Laboratory of the Brooklyn Institute, Cold Spring Har- 

 bor, Long Island, N. Y., and I wish to express my gratitude to Dr. C. B. 

 Davenport for the opportunity of carrying on investigations at the Sta- 

 tion. I wish also to thank Professor F. D. Barker, Professor H. B. Ba- 

 ker, and Mr. Elmer Shafer for kindly sending me material from which 

 parasites were obtained. 



The gregarines were studied in order to procure data in addition to 

 that already known concerning (1) their biology including the habitat, 

 relation to the host, seasonal distribution, and character of movement, 

 (2) their modes of reproduction, and (3) their systematic position; 

 twenty-two species are described for the first time while additional data 

 is given for many more species. One result of the work was the compila- 

 tion of a synopsis Avherein are recorded in concise form the known facts 

 concerning all the polycystid gregarines which literature records from 

 the Orthoptera, Coleoptera, and Myriapoda of the world. A list was 

 made of all the polcystid gregarines known, with their hosts, in order 

 that species may not be recorded as new which have hitherto been discov- 

 ered and that new species may not be given names which have already 

 been used. 



TECHNIC 



The following method \Vas used in studying the live parasites : The 

 anterior and posterior extremities of the host are clipped off as close to 

 the ends of the animal as possible and the alimentary tract is drawn out 

 intact. It is then slit lengthwise with fine scissors, placed flat on a slide, 

 and the masses of food and the parasites then teased out carefully to 

 form a layer as thin and as nearly transparent as possible. 



Distilled water and normal salt solution were found to be the best 

 media in which to observe the live gregarines. Plasmolysis is slower with 



