Key to the males of Helicopsychidae from Barro Colorado Island

1 Postantennal setal warts strongly enlarged and larger than the cephalic setal warts in

lateral view (fig. 42A in Johanson 2002); cephalic setal warts anteriorly swollen and separate from head capsule (fig. 42A in Johanson 2002) ................ H. tuxtlensis Bueno ­ Postantennal setal warts much smaller than the cephalic setal warts; cephalic setal warts not swollen anteriorly and fused with head capsule along its length .................. 2

2 Xth tergum with row of megasetae starting proximally on the segment; gonocoxite strongly sickle­shaped; basimesal lobe tuboid; phallus uniformly curving ventrally along its length ................................................................................. H. vergelana Ross

­ Xth tergum with megasetae present only on mid and distal part of the segment (Figs 5, 13); gonocoxite shape different (Figs. 4, 12); basimesal lobe cone­shaped (Figs 6, 14); phallus strongly curving ventrally at midlength (Figs 7, 15) ....................................... 3

3 Gonocoxite sharply incised toward basimesal lobe (Fig. 12); gonocoxite with basimesal lobe very long (Fig. 12); gonocoxite sharply triangular (Fig. 12); posterior margin of gonocoxite with prominent processes (Fig. 12) ................................. H. fridae sp.n.

­ Gonocoxite widely incised toward basimesal lobe (Fig. 4); posterior margin of gonocoxite with row of prominent processes (Fig. 4) or processes are lacking ................. 4

4 Gonocoxite (Fig. 4) parallelogram­shaped, and with row of processes at posteroventral margin; basimesal lobe (Fig. 6) with smooth lateral and median margins, and bearing about three stout megasetae .................................................................... H. woldai sp.n.

­ Gonocoxite widens slightly distally; posteroventral margin without processes; basimesal lobe with irregular median and lateral margins associated with numerous setae and no stout megasetae ................................................................................. H. incisa Ross