408 
Leidyaiia tiiiei n. sp. 
The wall of the cyst is about 8-10/x thick and is composed of many 
concentric layers of a highly refractive material (PI. IX, figs. 13, 14 c.w.). 
It is also surrounded by a thick outer layer of a transparent substance 
(PI. IX, fig. 13 ex.L). Dehiscence is produced by means of 2 to 5 short 
sporoducts (PI. IX, fig. 14 sp.). The spores are barrel-shaped and are 7 jx 
long (PI. IX, fig. 12). 
The infestation of the host is produced by ingestion of the spores 
and it is quite possible that the non-infected larvae may become infected 
after eating one of their own kind which contains the parasites. 
Cannibalism as a cause of heavy infection of Gryllus by Greyarina kingi 
Crawley was mentioned by Crawley (1907, p. 223). 
Systematic position. 
The following are the main characters of this gregarine: (a) sporont 
solitary; (b) epimerit subspherical, simple; (c) dehiscence by sporoducts; 
(d) spores barrel-shaped. These are quite sufficient to put this gregarine 
in the genus Leidyana Watson (1915) of the family of Gregarinidae. 
This genus has hitherto contained but two species: 
1. Leidyana erraiica (Crawley) Watson is a parasite of Gryllus 
abhreviatiis Serv. and of G. 'pennstjlvanicus Burm. Crawley (1903) at 
first considered this species to be identical with Leidy’s Gregarina 
achaeta abbreviala^. In 1907 he found that it differs from the latter 
species, and described it as a new one; but he did not find its cysts and 
put this species in the genus Stenopliora {Stenophora erratica Crawley, 
1907). He mentioned also that this species does not occur very often 
in Gryllus and that it must be identical with Stenophora juUpusili Leidy 
“somewhat altered from being in the wrong host.” 
The complete description and account of the life-cycle of this gregarine 
we owe to Watson (1916, pp. 118-120) who discovered the cysts and 
their method of dehiscence by sporoducts, and thus placed the species 
in its correct systematic position. 
2. Leidyana gryllorum (Cuenot) Watson is a parasite of Gryllus 
domesticus L. and is very similar to L. erratica. According to Watson 
(1910, pp. 120-121) “the only difference seems to be in the shape of 
the protomerit.” In A. erratica the protomerit “is decidedly conical at 
the apex” while in this species it is “broadly rounded subspherical in 
shape; the constriction at the septum is considerably deeper.” 
^ Also described by Diesing (1859) under the name Gregarina oviceps, which was 
accepted by Watson “as it is the oldest binomial name used.” 
