7] STUDIES ON GREGARINES—KAMM 



INTRODUCTION 



This monograph constitutes the second half of a problem in which it is 

 endeavored to bring together in small compass the more important facts 

 concerning the systematic position of polycystid gregarines. The first 

 part of the work (Watson, 1916a) was published in 1916 and included the 

 polycystid gregarines recorded from the Coleoptera, Orthoptera, and 

 Myriapoda of the world. The present paper comprises those from the 

 remainder of the animal kingdom. It is designed chiefly for the use of 

 workers on gregarines who do not have access to the vast literature which 

 has developed upon the subject and with which the University library is 

 so richly endowed. 



I wish to thank Professor Henry Baldwin Ward for kindly encouraging 

 the publication of this paper, for his advice and judgment concerning some 

 of the knotty systematic questions involved, and for the use of the labora- 

 tory and library facilities in his Department. 



When the first paper was published Dr. C. W. Stiles, of Washington, 

 informed me concerning the desirability of designating the type species 

 of the various genera, and this has been done in the present paper. He 

 also gave his opinion concerning the type species of the genus Cephaloido- 

 phora, for which I wish to express my thanks. 



The larger groupings used in the present paper are made from the 

 standpoint of the host-material rather than the parasite itself in order to 

 facilitate work in the field. From the descriptions it can be at once 

 determined whether or not a particular gregarine has ever been found in 

 identical or similar material. If it has not been described from hosts in 

 the same group and its position is definitely established from some one or 

 more of the generic characters, one may turn to the index of this and of the 

 preceding paper, where all the known species in each genus are ranged in 

 alphabetical order under the generic name. From a comparison of all 

 the known species wi^h the species in hand it may be determined whether 

 or not the latter has been described from some other group. It is true, 

 however, that except in rare instances a species is confined to a single 

 host or to nearly-related hosts, not being found in insects as far removed 

 from each other as the Coleoptera and the Orthoptera. 



In this paper I have not tabulated a complete alphabetic list of the 

 gregarine genera with their hosts or of the hosts with their parasites for this 

 reason: Two such lists were given in the former paper covering the species 



