Oocysts of Eimeria lateralis were isolated from feces of Spermophilus
richardsonii and compared to published descriptions of E. lateralis an
d Eimeria larimerensis from other spermophiline rodent hosts. A compar
ison of these 2 eimerian species, combined with an examination of host
specificity of spermophiline eimerians and host and parasite distribu
tions, suggests that E. larimerensis is synonymous with E. lateralis.