The Australian Lasioglossum Curtis 1833 subgenus Parasphecodes Smith 1853 is revised. Currently, Parasphecodes has 92 named, described species. The monotypic Lasioglossum subgenus Pseudochilalictus Michener 1965 is synonymised with Parasphecodes and its species, L. imitator Michener 1965, is recombined into Parasphecodes. The single known species from New Guinea, L. (Parasphecodes) permetallicum Michener 1965, is included in this revision. Eighteen new species are erected, 69 names are placed into synonymy, 20 new sex associations made and three species currently placed in Parasphecodes are recombined into the Lasioglossum subgenus Ctenonomia Cameron 1903. This revision resolved there are 40 valid species for Parasphecodes. Valid species for Lasioglossum (Parasphecodes) without synonymies are as follows: L. imitator, L. lichatus (Smith 1853), L. loweri (Cockerell 1905), L. olgae (Rayment 1935), L. permetallicum, L. turneri (Cockerell 1914d) and L. waterhousei (Cockerell 1915a). New synonymies proposed for Lasioglossum (Parasphecodes) are as follows: Lasioglossum (Pseudochilalictus Michener 1965) new synonymy = Lasioglossum (Parasphecodes); L. cirriferum (Cockerell 1910) new synonymy, L. insigne (Meyer 1920) new synonymy and L. grande (Meyer 1920) new synonymy = L. altichus (Smith 1853); L. paramelaenum (Cockerell 1922) new synonymy = L. atronitens (Cockerell 1914a); L. bribiense (Cockerell 1916) new synonymy, L. bribiensiforme (Cockerell 1930a) new synonymy, L. butleri (Rayment 1935) new synonymy, L. frenchi (Rayment 1935) new synonymy, L. frenchellum Michener 1965 new synonymy, L. sordidulum (Cockerell 1914c) new synonymy and L. patongensis (Rayment 1948) new synonymy = L. bryotrichum (Cockerell 1912a); L. fumidicaudum (Cockerell 1914b) new synonymy and L. noachinum (Cockerell 1914b) new synonymy = L. carbonarium (Smith 1853); L. cervicale (Cockerell 1915b) new synonymy and L. zamelanum (Cockerell 1930a) new synonymy = L. dissimulator (Cockerell 1914b); L. wilmatae (Cockerell 1929c) new synonymy = L. excultum (Cockerell 1913b); L. arciferum (Cockerell 1914b) new synonymy, L. atrorufescens (Cockerell 1914b) new synonymy, L. fulviventre (Friese 1924) new synonymy, L. leptospermi (Cockerell 1916) new synonymy, L. lichatinum (Cockerell 1922) new synonymy, L. leucorhinum (Cockerell 1926) new synonymy, L. proximum (Rayment 1947) new synonymy, L. testaciventre (Rayment 1953) new synonymy, L. tilachus (Smith 1853) new synonymy, L. tilachiforme (Cockerell 1907) new synonymy, L. tuchilas (Smith 1853) new synonymy, L. anhybodinum (Cockerell 1930a) new synonymy, L. hybodinum (Cockerell 1912a) new synonymy, L. tripunctatum (Cockerell 1929c) new synonymy and L. warburtoni (Cockerell 1906) new synonymy = L. hilactus (Smith 1853); L. frenchi (Cockerell 1904) new synonymy, L. schomburgki (Cockerell 1910) new synonymy, L. speculiferum (Cockerell 1912a) new synonymy, L. sextum (Cockerell 1910) new synonymy, L. solis (Cockerell 1922) new synonymy, L. vermiculatum (Cockerell 1914b) new synonymy and L. vulneratum (Cockerell 1910) new synonymy = L. hiltacus (Smith 1853); L. hirtiventre (Cockerell 1922) new synonymy, L. niveorufum (Friese 1924) new synonymy, L. submeracum (Cockerell 1930a) new synonymy and L. froggatti (Cockerell 1905) new synonymy = L. lacthius (Smith 1853); L. basilautum (Cockerell 1910) new synonymy, L. doddi (Cockerell 1914c) new synonymy, L. paracolletinum (Cockerell 1910) new synonymy, L. pilicolle (Friese 1924) new synonymy, L. scutellatum (Friese 1924) new synonymy and L. vau (Cockerell 1910) new synonymy = L. leichardti (Cockerell 1906); L. annexum (Cockerell 1922) new synonymy, L. latissimum (Cockerell 1915b) new synonymy, L. microdontum (Cockerell 1912a) new synonymy, L. recessum (Cockerell 1914d) new synonymy, L. longmani (Cockerell 1922) new synonymy, L. recantans (Cockerell 1912a) new synonymy and L. rufotegulare (Cockerell 1914e) new synonymy = L. melbournense (Cockerell 1904); L. trimaculatum (Friese 1924) new synonymy = L. musicum (Cockerell 1913a); L. gentianae (Rayment 1951) new synonymy = L. subrussatum (Cockerell 1922); L. fultoni (Cockerell 1914b) new synonymy, L. gibbosum (Friese 1924) new synonymy, L. niveatum (Meyer 1920) new synonymy, L. punctatissimus (Meyer 1920) new synonymy, L. rhodopterum (Cockerell 1914e) new synonymy, L. rubriventre (Friese 1924) new synonymy, L. subfultoni (Cockerell 1930a) new synonymy, L. tepperi (Cockerell 1905) new synonymy, L. notescens (Cockerell 1930a) new synonymy and L. rufulum (Friese 1924) new synonymy = L. sulthica (Smith 1853); L. submoratum (Cockerell 1930a) new synonymy and L. perustum (Cockerell 1914d) new synonymy = L. taluchis (Smith 1853). Eighteen new species are described as follows: L. acristum Walker & Sparks, L. altum Walker & Sparks, L. aspereticulum Walker & Sparks, L. atropum Walker & Sparks, L. bimelasmum Walker & Sparks, L. bipenicillum Walker & Sparks, L. bitrichum Walker & Sparks, L. blyscanatum Walker & Sparks, L. brevipectinatum Walker & Sparks, L. capronum Walker & Sparks, L. ferruginum Walker & Sparks, L. flexosum Walker & Sparks, L. laevidiscum Walker & Sparks, L. recavum Walker & Sparks, L. reticulum Walker & Sparks, L. rutrum Walker & Sparks, L. variegatum Walker & Sparks and L. wcisloi Walker & Sparks. New subgeneric classifications are as follows: L. (Pseudochilalictus) imitator = L. (Parasphecodes) imitator new status, Halictus clarigaster Cockerell 1918 = L. (Ctenonomia) clarigaster new status, Halictus forresti Cockerell 1906 = L. (Ctenonomia) forresti new status, and Halictus tribuarius Rayment 1935 = L. (Ctenonomia) tribuarium new status. These species names, all described by Smith 1853, are anagrams of Halictus. Therefore, they are nouns in apposition and should retain their original species designations as: Lasioglossum (Parasphecodes) altichus (Smith 1853), Lasioglossum (Parasphecodes) hilactus (Smith 1853), Lasioglossum (Parasphecodes) hiltacus (Smith 1853), Lasioglossum (Parasphecodes) lacthius (Smith 1853), Lasioglossum (Parasphecodes) lichatus (Smith 1853), Lasioglossum (Parasphecodes) sulthica (Smith 1853), Lasioglossum (Parasphecodes) talchius (Smith 1853), Lasioglossum (Parasphecodes) taluchis (Smith 1853), Lasioglossum (Parasphecodes) tilachus (Smith 1853) and Lasioglossum (Parasphecodes) tuchilas (Smith 1853). All 40 valid Parasphecodes species, as well as the three species recombined to Ctenonomia, are redescribed. For the Parasphecodes species, keys to both sexes, character groups, taxonomy, citations, species diagnoses, comments, descriptions, scanning electron micrographs, colour montage images, distribution maps, male genitalia and S7S8 line drawings are provided to assist with species identifications.