Low-energy electron bombardment of cyclopropane submonolayers was used to prepare cyclopropyl and metallacyclobutane species on Cu(110) and Cu(111) surfaces. The thermal chemistry of both species was monitored over the 90-450 K range by taking high-resolution electron energy loss (HREELS) and temperature programmed desorption (TPD) measurements. Cyclization of the metallacyclobutane species, to eliminate cyclopropane, was found to occur at 205 K. The metallacyclobutane species was characterized by CH stretching losses at 2806 and 2839 cm(-1) for Cu(110) and Cu(111), respectively. The cyclopropyl species was found to undergo ring opening to yield a propene desorption product at 290 K. The observed surface chemistry of both of these cyclic C-3 species is compared with data from the organometallic, catalysis, and surface science literature.