42 ILLINOIS BIOLOGICAL MONOGRAPHS [252 



characteristics : Size, both medium and average ; ratio of length of proto- 

 merite to total length; ratio of width of protomerite to width of deuto- 

 merite ; general shape of the body ; shape of the protomerite ; shape of the 

 deutomerite ; character of the interlocking device ; size and shape of the 

 nucleus; color and character of the protoplasm; and the size and shape 

 of the cysts and their method of dehiscence. 



It is true of many species that the family or generic determination 

 or both are uncertain because important diagnostic features such as the 

 epimerite and spores are oft^n lacking. The correct family can some- 

 times be determined when only one of these factors is present. In some 

 instances the correct genus can be ascribed even though important data 

 are lacking, e. g. the genus Grcgarina, by its biassociative factor and the 

 host involved. If there is any doubt about the position of a given ani- 

 mal, the parasite is placed at the end of the particular genus to which it 

 may belong. 



In describing the associative gregarines, generally only specific 

 measurements of the primite are given for the proportions of satellite 

 diifer considerably within the same species as it happens to be more or 

 less flattened while those of the primite remain fairly constant. The 

 shape given for the posterior end of the deutomerite is that of the satel- 

 lite, where the deutomerite is free at its posterior end ; in the primite it 

 is altered by contiguity with the protomerite of the primite. 



The species of gregarines indigeneous to each of the three groups 

 are arranged in families, and under each family the genera are placed 

 in alphabetical order. In each genus the species are arranged in chrono- 

 logical order, the oldest first, the latest additions last. New species not 

 hitherto found are described in detail in the groups to which their hosts 

 belong. 



In as many instances as possible, the names of the hosts have been 

 checked and corrected to accord with the best authorities. However, this 

 has often been impossible and the names had to be left as in the original 

 citation. Especially is this true of the older species of parasites, many of 

 which have not been found since the original discovery seventy-five years 

 or more ago. 



The names of the Myriapod hosts have been corrected, those abroad 

 in accordance with Latzel (1884) and those endemic to the United States 

 after BoUman (1893). Coleopteran literature seems not to be in condi- 

 tion to warrant the finding of synonyms for many of the early described 

 species. For instance, the name by which a beetle is known today will 

 be recorded, but not the name by which it was known some fifty years 

 ago and by which it was called when the parasites infesting it were de- 

 scribed. "When names have been corrected to accord with present day 



