1. Antennal segment III with 2 sense cones.................................................................................................... 2
- Antennal segment III with 3 sense cones.................................................................................................... 4
2. Antennal segment IV with 3 sense cones; glandular area shuttle-shaped on abdominal sternite VIII of male (Fig. 8) ........................................................................................................................ P. elagatus sp. n.
- Antennal segment IV with 2 sense cones; glandular area on abdominal sternite VIII of male not shuttle- shaped......................................................................................................................................................... 3
3. Cheeks slightly widened at base of head; postocellar setae short, usually less than 20 microns; glandular area on abdominal sternite VIII of male transversely elongated ......................................... P. simplus Haga
- Cheeks weakly narrowed at base of head; postocellar setae usually more than 20 microns; glandular area on abdominal sternite VIII of male narrow and arched ............................... P. chebalingicus Zhang & Tong
4. Antennal segment IV with 3 sense cones................................................................................................... 5
- Antennal segment IV with 4 sense cones................................................................................................... 8
5. Fore tarsal tooth present in both sexes........................................................................................................ 6
- Fore tarsal tooth absent in female............................................................................................................... 7
6. Tube brown; abdominal segments IV to IX yellowish brown; antennal segment VIII longer than VII (Fig. 18) ..................................................................................................................................... P. longidens sp. n.
- Tube brownish yellow; abdominal segment IX brown; antennal segment VIII almost as long as VII........ ....................................................................................................................................... P. armatus Okajima
7. Postocular and epimeral setae with apices expanded; cheeks constricted behind eyes ..... P. amens Priesner
- Postocular and epimeral setae with apices pointed; cheeks almost straight, not constricted behind eyes (Fig. 11) ......................................................................................................................... P. bicoloratus sp. n.
8. Antennal segments IV-VIII yellowish; B 1 of abdominal tergum IX much shorter than B 2 and tube...................................................................................................................................................... P. lewisi (Bagnall)
- Antennal segments III-VIII yellowish brown; B 1 of abdominal tergum IX longer than B 2 and tube........................................................................................................................................ P. ascitus (Ananthrishnan)