Pemphredon brevipetiolata WAGNER 1932; Pemphredon dispar VALKEILA 1972; Cemonus fabricii MÜLLER 1911; Diphlebus fuscatus WAGNER 1918; Pemphredon gemina VALKEILA 1972; Pemphredon lethifera misspelling; Pemphredon levinota MERISUO 1972; Diphlebus littoralis WAGNER 1918; Pemphredon minor GUSSAKOVSKIJ 1952; Diphlebus minutus WAGNER 1918; Pemphredon nannophyes MERISUO 1972; Diphlebus neglectus WAGNER 1918; Pemphredon platyura GUSSAKOVSKIJ 1952; Cemanus strigatus CHEVRIER 1870; Pemphredon sudaorum TSUNEKI 1977; Pemphredon trichogastor VALKEILA 1972
The genus Pemphredon has more than its fair share of synonyms amongst its species and the fauna of Great Britain and Ireland has several species with more than their 'fair share' of these. Pemphredon lethifer may be readily bred from nests in the pith of old bramble stems. The nest architecture is distinctive, a spiral tunnel with cells 'dropping off the spiral parallel to the outside of the stem at intervals. However, the resulting adults are confusingly varied, both in size and finer details of the ratios of different body parts. This small-scale variability has given rise to a wide range of applied names throughout its range.
In 1995 H. Dollfuss (A Worldwide Revision of Pemphredon LATREILLE 1796 (Hymenoptera Sphecidae). Linzer biol. Beitr. 27/2: 905-1019) dealt with many of these synonyms, including P. austriaca f enlsini. (Wagner, 1932). O.W.R. Richards in his 1980 RES key to the Scolioidea, Vespoidea and Sphecoidea recognised this as P. enslini (Wagner), but did preface the entire section with a warning that the treatment must be regarded as provisional. Further confusion for British and Irish entomologists resulted from an erroneous decision in BWARS to equate P. austriaca f enslini with P. austriaca. This latter name is still considered to represent a distinct taxon, but one which has never been recorded in the British Isles. This confusion has been further added to by arguments over grammatical agreements (related to Latin) within the genus as a whole, hence lethifera was promoted as the correct name for a while.
Richards' comment about the difficulty of separation and status of some of the supposed species is still very much to the fore and has been recently echoed by Dollfuss (pers comm), but the name P. lethifer does seem to have some basis - even if the physical characters distinguishing it from P. inornata are very difficult to recognise in all specimens. This latter species, however, does not nest in the pith of old bramble stems.
Richards (1980) considered this species to be common and found throughout England, Wales, southern Scotland and Ireland. Work for this atlas shows a distribution similar to that of P. inornata.
It is reasonably widespread in southern Scandinavia and is found across much of the Palaearctic to the Far East. It has been introduced to North America (Lomholdt, 1984). Bitsch et al. (2001) add North Africa and several Middle East countries.