110 ILLINOIS BIOLOGICAL MONOGRAPHS [320 



In the following characteristics, the two species agree : 



Ratio 



length protom. : total length primite 1:5 1:5 



length protom. : total length satellite 1:8 1:8 



' Shape protomerite of 



primite Hemispherical Hemispherical 



Nucleus Spherical Spherical 



On the strength of the shape of the posterior end of the body, the 

 shape of the satellite, and in the regularity in shape of the body there 

 is basis for the creation of a new species, although in one important 

 factor, proportions, the two species agree. There are no measurements 



stated for the Old World species. Schneider says '' elle devient 



tres-volumineuse " which indicates that the species may be as large as 

 the one here described. The species described by Leidy (1853:239) 

 from Blatta orientalis agrees in size with both species. His drawings 

 indicate an irregularly shaped body and a more or less sharply pointed 

 posterior extremity and the hosts he dissected were probably the intro- 

 duced European cockroach and the gregarine the Old World G. hlat- 

 tarum. 



Crawley records (1903:44) the species G. hlattaruni as 



"Common in Perit>laneta orientalis, P. americana and Ectobia (Blatta) ger- 

 manica. A few specimens of Ischnoptera pennsylvanica, the field cockroach, were 

 examined, but none contained gregarines." 



These hosts undoubtedly yielded the same parasites which Leidy also 

 had found at Philadelphia. 

 Ellis (1913b :83) says: 



"This gregarine was found in several specimens of the native roach Ischnop- 

 tera penttsylvanica from the woods near Douglas Lake. - - Although no intro- 

 duced roaches have been collected in the vicinity , this gregarine from native 



roaches seemes undoubted the typical G. blattarum, agreeing in spores, cysts and 

 sporonts with that species. The biological question of interest is, of course, the 



source of infection of these native roaches. It is possible, however, that G. 



blattarum is established in the native roaches in the new world. both Fren- 



zel and Magalhaes found the native roaches to be infected with gregarines other 

 than G. blattarum ." 



In his Syllabus (1913b :265), Ellis gives measurements which coincide 

 fairly well with those recorded above in the table. The maximum 

 length of a sporont he states to be 520/*, while that of the above species 

 is 560/t. He says 



"Cysts prolate spheroids, average 450 x QOOfi - -, spore ducts 10 or more, 

 reaching the length of 200^ ; sporocysts barrel-shaped, 4 x 8^," 



