Key to the Form I Males of the Hagenianus Group of Procambarus (Girardiella) Lyle, 1938

1a. Without long median spine that overlaps the distal margin of the mesial lobe of the uropods (Figure 5 b)..................................................................................................... Gracilis Group species

1b. With long median spine that overlaps the distal margin of the mesial lobe of the uropods (Figure 5 a)..................... Hagenianus Group species ............................................................................. 2

2a. Caudal process in lateral view rhomboidal in outline, distally with an elongated straight edge (Figure 4 C)............................................................................................. Procambarus hagenianus …3

2b. Caudal process in lateral view triangular in outline, distally coming to a sharp point (Figure 4 A&B).................... 4

3a. Lateral margin of palm of chelae without a beard of dense long setation, sometimes with short hairs in pits anterior to tubercles (Figure 22 A–D)........................................................ Procambarus hagenianus hagenianus

3b. Lateral margin of palm with a beard of dense setation, sometimes less dense but with long setae (Figure 21 A&B).................................................................................. Procambarus hagenianus vesticeps

4a. Caudal process in lateral view an acute triangle, distinctly shorter than the central projection (Figure 4 A); lateral margin of palm of chelae without a beard of dense setation (Figure 1 N).................................. Procambarus holifieldi

4b. Caudal process in lateral view an obtuse triangle, subequal in length to the central projection (Figure 4 B); lateral margin of palm of chelae with a beard of dense setation (Figure 13 M)................................... Procambarus barbiger