III. — A Study of Sojjic Grcgarincs zuith Especial Reference to 

 Hirmocystis rigida n. sp^ 



BY MAURICE GROWTH ER HALL. 



A study of some of the gregarines found in the vicinity of Lin- 

 cohi, Nebraska, was begun about the first of October, 1905. 

 Gregarines were found in Periplaneta americana, in Jnlus sp., 

 and in three genera of the Acridoidea, representing three sub- 

 families, as follows : the Acridiinae, represented by McIaiwpliLS 

 differentialis, M. femur-rnbrum, and M. atlaiitis; the Oedop- 

 odinae, represented by Chimarocc phalli s viridifasciata and C. 

 viridifasciata var. infuscata; and the Truxalinae, represented by 

 Eritcttix sp. 



The gregarine from Periplaneta was found to be Grcgarina 

 blattaruni Sieb. 1839; that from Jnlus is the form listed by Craw- 

 ley as Stenophora juUpusilli Leidy 1853 ; while those from the 

 remaining forms are from new hosts and are apparently unde- 

 scribed species. The old forms were studied in connection with 

 the new to give a basis for morphological and physiological com- 

 parison, and require little special note aside from the record of 

 their occurrence in this locality. 



Grcgarina hlattarum was fairly common in Periplaneta, but for 

 some reason was not found in Blaita (Ectobia) gcrnianica from 

 the same neighborhood. A single cyst ripened in water for 

 thirty-six days with an air temperature of i8°C. was sectioned 

 and showed the sporocysts with their nuclear content in various 

 stages of development, a notable delay beyond the normal ripen- 

 ing period of less than a week gii^en for this form by Biitschli 

 (1881) and Magalhaes (1900). 



^Studies from the Zoological Laboratory, The University of Nebraska, 

 under the direction of Henry B. Ward, No. 77. 



University Studies, Vol. VII, No. 2, April 1907. 



149 



