Key to species of Arphthicarus Niedbała, 1994 of Madagascar

1. Interlamellar setae short spiniform as lamellar setae.......................................................... 2

-. Interlamellar setae rather long, thick, erect covered with small spines in distal half.................................. 3

2. Sensilli with short, narrow pedicel and globular head; setae d of femora I situated at middle of article.................................................................... A. paratinctus Niedbała & Starý, 2015 (Niedbała & Starý 2015d)

-. Sensilli long, narrow, falcate; setae d of femora I situated at distal end of article...................... A. phoxos sp. nov.

3. Notogastral setae c 3 and cp distinctly shorter than other setae and bent...... A. inelegans (Niedbała, 1986) (Niedbała 1986b)

-. All notogastral setae similar in shape..................................................................... 4

4. Setae ro shorter and distance between them 3 times shorter than distance between setae in; notogastral setae obtuse distally; setae c 1 slightly remote from anterior border, setae c 2 and c 3 more remote from border...... A. veteratorius (Niedbała, 1988)

-. Setae ro longer and distance between them similar to distance between setae in; notogastral setae pointed distally; setae c 2 remote more from anterior border than setae c 1 and c 3......................................................... 5

5. Sensilli rounded distally, notogastral setae shorter (c 1<c 1– d 1), adanal setae ad 2 and ad 3 located near paraxial margin...................................................................................... A. sculptilis (Niedbała, 1988)

-. Sensilli pointed distally, notogastral setae longer (c 1> c 1– d 1), adanal setae ad 2 and ad 3 remote from paraxial margin....................................................................................... A. trichosus (Mahunka, 1988)