Key to species of the tectum group

1 Lateroapical angles of pronotum distinctly protruding anteriad................................................. 2

- Lateroapical angles of pronotum not or indistinctly protruding anteriad........................................... 3

2 Pronotum twice as broad as long. Median lobe wide (Fig. 67). Body length: 2.80–4.50 mm. Habitus as in Fig. 82. Siberia.............................................................................................. A. frigidum

- Pronotum distinctly less than twice as broad as long. Median lobe narrow (Fig. 99). Body length: 4.20 mm. Habitus as in Fig. 95. Tajikistan ............................................................................ A. tichomirovae

3 Elytra about as long as broad or slightly longer.............................................................. 4

- Elytra slightly broader than long......................................................................... 7

4 Mediobasal third of pronotum with indistinct semicircular impression.Apical portions of parameres very wide (Fig. 103). Body length: 3.10 mm. Habitus as in Fig. 97. Nepal ........................................................ A. vitreum

- Mediobasal third of pronotum without impression. Apial portions of parameres narrow or relatively wide............... 5

5 Pronotum slightly more narrowed posteriad than anteriad. Apical portion of median lobe gradually narrowed toward rounded apex (Fig. 87). Body length: 2.65–3.25 mm. Habitus as in Fig. 4. Nepal ............................... A. himalayense

- Pronotum evenly narrowed both anteriad and posteriad. Apical portion of median lobe wide, with truncate apex.......... 6

6 Median lobe wide; parameres moderately short, slightly exceeding apex of median lobe (Fig. 63). Body length: 2.70–4.50 mm. Habitus as in Fig. 2. Trans-Palaearctic............................................................... A. tectum

- Median lobe narrow; parameres long significantly exceeding apex of median lobe (Fig. 65). Body larger: 3.40–3.60 mm. Habitus as in Fig. 3. China: Sichuan ............................................................... A. cornatipenis

7 Body with bluish reflex in middle of head, neck and medioapical portion of pronotum. Aedeagus as in Fig. 89. Body length: 2.81–3.35 mm. Habitus as in Fig. 5. China: Sichuan ............................................ A. multipunctatum

- Body without bluish reflex.............................................................................. 8

8 Antennomeres 6–10 elongate. Median lobe moderately wide (Fig. 91). Body length: 3.15–3.90 mm. Habitus as in Fig. 94. China: Xizang ................................................................................ A. smetanai

- Antennomeres 6–10 slightly transverse. Median lobe very wide (Fig. 101). Body smaller: 3.00 mm. Habitus as in Fig. 96. China: Yunnan .............................................................................. A. umbrinum