118 ILLINOIS BIOLOGICAL MONOGRAPHS [328 



The protoplasm is dense, tan in the protomerite and black in the deu- 

 tomerite. The nucleus is spherical and is visible only in young speci- 

 mens. 



Cysts and the epimerite were not seen. 



Some of the more important measurements, with all dimensions 

 given in microns, follow : 



Total length association 600 580 500 



Primite : 



Length protomerite 60 50 50 



Length deutomerite 250 220 200 



Width protomerite 100 100 60 



Width deutomerite 200 130 110 



Length sporont 310 270 250 



Eatio 



length protom. : total length 1 :5.1 1 :5.4 1 :5 



width protom. : width deutomerite 1 :2 1 :1.3 1 :1.8 



Satellite : 



Length protomerite 40 50 50 



Length deutomerite 250 260 200 



Width protomerite : 140 100 80 



Width deutomerite 190 120 110 



Length sporont 290 310 250 



Ratio 



length protom. : total length 1 :7.2 1 :6.2 1 :5 



width protom. : width deutomerite 1 :1.3 1 :1.2 1 :1.3 



This species differs from Gregarina longiducta Ellis in length of the 

 sporonts and in shape of the protomerite ; and from G. consobrina Ellis 

 in shape and proportions of the protomerite; it differs from G. stygla 

 Watson in size and shape. 



The hosts from which all these gregarines are taken are various spe- 

 cies of the genus Ceuthophilus, which is closely related to the genus Udeo- 

 psylla. The parasite in question is readily distinguished from the above 

 species by the cone-shaped protomerite of the primite. 



LEIDYANA EERATICA (Crawley) Watson 



[Figures 208, 218-56] 



1903 Gregarina achetaeabbreviatae Crawley 1903 :45 



1907 Stenophora erratica Crawley 1907 :221 



1915 Leidyana solitaria Watson 1915 :35 



Hosts: Gryllus abbreviatus Serv. and G. pennsylvanicus Burm. 

 The parasites were taken at Cold Spring Harbor and Oyster Bay, L. 

 I., Haverford, Pa., and at Urbana, Illinois, during the summer and fall 

 of 1914. 



