Macrostomum appendiculatum sillimani Ferguson, 1939 accepted as Macrostomum appendiculatum Fabricius, 1826 (original description)
Macrostomum beauchampi Ferguson, 1939 accepted as Macrostomum elgonense (de Beauchamp, 1935) (original description)
Macrostomum carolinense (Ferguson, 1940) (original description)
Macrostomum collistylum Ferguson, 1939 (original description)
Macrostomum curvistylum Ferguson, 1939 (original description)
Macrostomum finnlandense (Ferguson, 1940) (original description)
Macrostomum frigorophilum (Ferguson, 1940) (original description)
Macrostomum gieysztori Ferguson, 1939 (original description)
Macrostomum gilberti Ferguson, 1939 (original description)
Macrostomum glochistylum Ferguson, 1939 (original description)
Macrostomum glochostylum Ferguson, 1939 accepted as Macrostomum glochistylum Ferguson, 1939 (original description)
Macrostomum glocostylum Ferguson, 1939 accepted as Macrostomum glochistylum Ferguson, 1939 (original description)
Macrostomum graffi Ferguson, 1939 (original description)
Macrostomum granulophorum (Ferguson, 1940) (original description)
Macrostomum lewisi Ferguson, 1939 (original description)
Macrostomum recurvostylum (Ferguson, 1940) (original description)
Macrostomum reynoldsi Ferguson, 1939 (original description)
Macrostomum riedeli Ferguson, 1939 (original description)
Macrostomum ruebushi carolinensis Ferguson, 1940 accepted as Macrostomum carolinense (Ferguson, 1940) (original description)
Macrostomum ruebushi crenatostylum Ferguson, 1940 (original description)
Macrostomum ruebushi finnlandensis Ferguson, 1940 accepted as Macrostomum finnlandense (Ferguson, 1940) (original description)
Macrostomum ruebushi frigorophylum Ferguson, 1940 accepted as Macrostomum frigorophilum (Ferguson, 1940) (original description)
Macrostomum ruebushi granulophorum Ferguson, 1940 accepted as Macrostomum granulophorum (Ferguson, 1940) (original description)
Macrostomum ruebushi recurvostylum Ferguson, 1940 accepted as Macrostomum recurvostylum (Ferguson, 1940) (original description)
Macrostomum ruebushi shenandoahensis Ferguson, 1940 accepted as Macrostomum shenandoahense (Ferguson, 1940) (original description)
Macrostomum ruebushi truncatum Ferguson, 1940 accepted as Macrostomum truncatum (Ferguson, 1940) (original description)
Macrostomum sensitivum Silliman, 1884 accepted as Macrostomum appendiculatum Fabricius, 1826 (source of synonymy)
Macrostomum shenandoahense (Ferguson, 1940) (original description)
Macrostomum tennesseense Ferguson, 1939 (original description)
Macrostomum truncatum (Ferguson, 1940) (original description)
Promacrostomum gieysztori (Ferguson, 1939) accepted as Macrostomum gieysztori Ferguson, 1939 (original description)

Black Sea for Macrostomum graffi Ferguson, 1939 
Connecticut for Macrostomum ruebushi granulophorum Ferguson, 1940 
Connecticut for Macrostomum ruebushi recurvostylum Ferguson, 1940 
Finland for Macrostomum ruebushi finnlandensis Ferguson, 1940 
New York for Macrostomum appendiculatum sillimani Ferguson, 1939 
North Carolina for Macrostomum ruebushi carolinensis Ferguson, 1940 
Tennessee for Macrostomum collistylum Ferguson, 1939 
Tennessee for Macrostomum gilberti Ferguson, 1939 
Tennessee for Macrostomum ruebushi Ferguson, 1940 
Tennessee for Macrostomum ruebushi crenatostylum Ferguson, 1940 
Tennessee for Macrostomum ruebushi crenatostylum Ferguson, 1940 
Tennessee for Macrostomum ruebushi crenatostylum Ferguson, 1940 
Virginia for Macrostomum bulbostylum Kepner & Stiff, 1932 
Virginia for Macrostomum curvistylum Ferguson, 1939 
Virginia for Macrostomum glochostylum Ferguson, 1939 
Virginia for Macrostomum lewisi Ferguson, 1939 
Virginia for Macrostomum reynoldsi Ferguson, 1939 
Virginia for Macrostomum riedeli Ferguson, 1939 
Virginia for Macrostomum ruebushi Ferguson, 1940 
Virginia for Macrostomum ruebushi frigorophylum Ferguson, 1940 
Virginia for Macrostomum ruebushi shenandoahensis Ferguson, 1940 
Virginia for Macrostomum ruebushi shenandoahensis Ferguson, 1940 
Virginia for Macrostomum ruebushi truncatum Ferguson, 1940