Sphecodes from Saskatchewan

4 p. ; 24 cm.Includes 1 bibliographical reference (p. [1])

Plumage of the Eocene bird Diatryma

4 p. : ill. ; 24 cm.Includes bibliographical references

Genus Andrena

20 p. ; 23 cm

Nocturnal bees and a minute Perdita

4 p. : ill. ; 24 cm

Genotypes of American Tertiary insects

p. 77-86 ; 24 cm

New fossil species of Unio

p. 121-126 : ill. ; 24 cm.Includes bibliographical references

Tertiary land shells from Wyoming

p. 323-325 : ill. ; 24 cm.Includes bibliographical references

Fauna of Sunchal Formation, Argentina

9 p. : ill. ; 24 cm.Includes bibliographical references

Chinese bees

3 p. : ill. ; 23 cm