1	Chaetotaxy of sternite VIII 4/0	2
–	Chaetotaxy of sternite VIII 4/2	3
2	Seta x present; rostrum very long, LR = 3,3	Acerentomon noseki Torti, 1981
–	Seta x absent; rostrum short, LR ≥ 6	4
3	Seta x present; rostrum long, LR = 3,5–4,7	7
–	Seta x absent; rostrum of medium length, LR = 4,5–5	Acerentomon affine Bagnall, 1912
4	Rostrum short, LR nearly 6	5
	Rostrum very short, LR ≥ 9	6
5	Sensillum b extremely broad, not spindle–shaped and shorter than c; a long and reaching the base of e; pleural pectines strongly developed	Acerentomon meridionale Nosek, 1960
–	Sensillum b broad, spear shaped, almost reaching seta γ4 and longer than c; a short, barely reaching the base of d; pleural pectines only on segments VI–VII	Acerentomon balcanicum Ionescu, 1933
6	Comb VIII with 10–14 teeth; pleural pectin VI with a row of long teeth; ratio of sensilla a:b = 1,1	Acerentomon microrhinus Berlese, 1909
–	Comb VIII with 17–20 teeth; pleural pectin VI strongly reduced to a group of 4 distinct teeth; ratio of sensilla a:b = 0,8	Acerentomon condei Nosek & Dallai, 1982
7	Sensillum b thin and small, distinctly shorter than c	8
–	Sensillum b distinctly broad, subequal or longer than c	10
8	Head with additional setae	Acerentomon gallicum Ionescu, 1933
–	Head without additional setae	9
9	Sensillum a short, barely reaching d; pleural line VI with a fine serration	Acerentomon italicum Nosek, 1969
–	Sensillum a long, extending beyond the base of d, sometimes even reaching e; pleural line VI with a row of conspicuous teeth	Acerentomon fageticola Rusek, 1966
10	Seta p3’ present in tergite VII	Acerentomon doderoi Silvestri, 1907
–	Seta p3’ missing in tergite VII	11
11	Comb VIII with 14–16 long teeth, the median ones smaller; body length about 1600 μm	Acerentomon maius Berlese, 1908
–	Comb VIII with 9–12 pointed teeth; body length 1980–2370 μm	Acerentomon baldense Torti, 1986