Cephalastor is a small neotropical genus of potter wasps (Hymenoptera: Vespidae: Eumeninae) currently containing 14 species.

The known species are:

• Cephalastor sinusiticus Garcete-Barrett, 2002 (Mexico)
• Cephalastor lambayeque Garcete-Barrett, 2002 (Coastal Peru)
• Cephalastor bossanova Garcete-Barrett, 2002 (Southern Brazil)
• Cephalastor estela Garcete-Barrett, 2002 (Paraguay and Brazil)
• Cephalastor humeralis Garcete-Barrett & Hermes, 2009 (Brazil)
• Cephalastor mariachi Garcete-Barrett, 2001 (Mexico)
• Cephalastor minarum Garcete-Barrett & Hermes, 2009 (Brazil)
• Cephalastor abraham Garcete-Barrett, 2001 (Ecuador)
• Cephalastor tupasy Garcete-Barrett, 2001 (Peruvian Amazon)
• Cephalastor relativus (Fox, 1902) (Suriname, Eastern Colombia, Ecuador, Bolivia and Central Brazil)
• Cephalastor rufosuffusus (Fox, 1902) (Guyana, Central Brazil and Paraguay)
• Cephalastor paezi Garcete-Barrett, 2001 (Colombian Llanos)
• Cephalastor rominae Garcete-Barrett, 2001 (Paraguayan Chaco)
• Cephalastor chasqui Garcete-Barrett, 2001 (Eastern Bolivia and Andean Peru)

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