42 Psyche [March-June 
rather medial position of hump, shorter (comparatively to men- 
tum) rostellem and conspicuously longer teeth. 
Measurements (in mm.): aedeagus, 0.95, suprazonal portion 
0.45, subzonal 0.5 with breadth (lateral view) 0.12; penis 0.85. 
Furca 0.7. Vertical/Horizontal extension of uncus: forearm 
0.29/0.05, humerulus 0.06/0.2, shoulder 0.15/0.06, lobe 
0.4/0. 9. Valve 1.1 (to comb 1.2) with breadth 0.44; average 
length of teeth 0.017. 
Itylos koa Druce 
(fig. KOA, pi. 6, 7) 
Two males and one female investigated (Mus. Comp. Zool.) : 
prep. 592, 595 and 593 female, “Puno, Peru, 12,500 ft. alt., 
l-XI-1898” ex coll. Weeks. 
Separated in uncus and valve from the precedent structures 
by a wider hiatus than that existing between moza and ruber- 
rothei on one hand and pads on the other, ^deagus slightly 
shorter and thinner than in pacts , furca slightly longer. Fore- 
arm shorter, rather thicker at its base, then tapering, shoulder 
smaller, uncus lobe about six times as long as broad, much nar- 
rower throughout than in the other species. Valve smaller, 
rather proximally humped, hardly more than half as long as 
broad, only slightly longer than the aedeagus, with a correspond- 
ingly reduced comb, very minutely serrated, the teeth a third 
shorter than in ruberrothei. 
Measurements (in mm.) [when different, 592 quoted first]: 
aedeagus 0.84 and 0.8, suprazonal portion 0.42 and 0.4, subzonal 
portion 0.42 and 0.4 with breadth (lateral view) 0.08; penis 0.8 
and 0.75. Furca 0.76. Vertical/Horizontal of uncus: forearm 
0.23/0.05 and 0.25/0.05, humerulus 0.08/0.13 and 0.1/0.17, 
shoulder 0.13/0.05 and 0.17/0.06, lobe 0.31/0.06 and 0.3/0.055. 
Valve 0.9 (to comb 1) with breadth 0.41 and 0.42; average 
length of teeth 0.004. 
The “vitta” of British authors is a certain combinational pat- 
tern element occurring on the hindwing underside of a number 
of Palaearctic Plebejinx (and especially conspicuous in certain 
Agrodicetus species). It is made up of halo and cretule fusions 
and can be divided into four phases of development: 1. halo M 2 
(its posterior distal part) and cretule M 2 fuse in the posterior 
part of the cell, i.e ., below the interneural fold in M 2 , the result- 
ing white streak occupying the whole space between the fold 
