321] STUDIES ON GREG ARINES— WATSON 111 



Ellis' drawing differs somewhat in shape from that of any specimen 

 seen by the present writer (ratio length protomerite : total length 

 primite in the former 1 : 3.3, in the latter 1:5) but this is not suffi- 

 cient to constitute a new species as it is the only difference in the two. 

 It is highly probable that but one species is involved. Ellis' specimens 

 were taken from Ischnoptera pennsylvanica (de Geer) at Douglas Lake, 

 Mich. 



Hall (1907) makes the simple statement that 'Periplmieta americana 

 contains Grcgarina hlattarum. I have no reason to doubt its presence. 



It is to be noted that the terms Blatta orientalis and Periplaneta o. 

 are used interchangeably by various authors, the name now accepted 

 being Blatta orientalis L. 



GREGARINA GALLIVERI Watson 

 [Figures 205, 275-290] 

 1915 Gregarina galliveri Watson 1915:33-34 



Host: Gryllus a'hhreviatus Serv. 



This species was taken at Oyster Bay, Long Island, in August, 

 1914. The parasite lives in the intestine of the host. The species is 

 rare, being seen only three times in a hundred or more crickets opened, 

 sixty-five associations and five cysts being found in a single host, and 

 a dozen or more associations in each of the other two. In the first 

 named, nearly all the associations were engaged in cyst making. 



The sporonts are biassociative, even to the smallest seen. The 

 maximum length of an association seen was 590/*, the maximum width 

 180/x. The animals are quite polymorphic but certain generalizations 

 can be made. The protomerite of the primite is always wider than the 

 deutomerite. Measurements indicate that it is but little wider, but 

 the difference seems much greater because the two places of greatest 

 width, those used in the table of measurements, are widely separated. 

 The protomerite is low and broad, either flat or very slightly rounded 

 at the anterior end and from two to four times as wide as high, the 

 average being three. Its widest part is in the middle, where it is ap- 

 proximately one and a half times as wide as the septum. The proto- 

 merite of the satellite is considerably narrower than that of the primite. 

 It is greatly flattened and from two to four times as wide as high. The 

 deutomerite of the primite is constricted a little just below the septum, 

 widening out below the middle where it attains nearly the measured 

 width of the protomerite. In some instances it is nearly cylindrical. 

 The deutomerite of the satellite is irregularly subglobular to broadly 



