The series I-b of Aphodius was erected by Dr. Horn for those of our species which have the fore tibia punctate on the anterior face and the first segment of the anterior tarsus longer than the second. Horn including two species, rubeolus and stercorosus, in this group, overlooking the fact that two additional species known to him, lentus and tenuistriatus, possessed these characters. Subsequently, troglodytes and campestris were described by Hubbard and Blatchley respectively. The present paper includes the six species noted above and adds two which are described as new. Aphodius canadensis Garnett, described as a member of this group, is omitted, for in it the anterior tibia is impunctate, the first segment of the anterior tarsus is shorter than the second, and the pronotal side margins are explanate; the species is a member of series I-a.