A revision of the Neotropical caddisfly genus Leucotrichia Mosely, 1934 (Hydroptilidae, Leucotrichiinae) Thomson, Robin E. Holzenthal, Ralph W. ZooKeys 2015 499 1 100 http://zoobank.org/FA7318B2-146B-4F39-81C4-EFED47096C09 Thomson & Holzenthal Insecta Hydroptilidae Leucotrichia CoL Animalia Leucotrichia dianeae Trichoptera 15 16 Arthropoda species dianeae  Taxon classification Animalia Trichoptera Hydroptilidae  Diagnosis. This species is similar to Leucotrichia bicornuta, Leucotrichia extraordinaria, and Leucotrichia tapantiasp. n. These species share a similar combination of characteristics present in the phallus and the posterolateral margin of sternum VIII, as discussed under Leucotrichia bicornuta. Of these species, Leucotrichia dianeaesp. n., is most similar to Leucotrichia tapantia, as discussed under Leucotrichia tapantia. The apical lobes of the phallus apex of Leucotrichia dianeaearise from the same apicomesal location on the apex, while those of Leucotrichia tapantiaare separated from each other in more apicolateral locations. Additionally, the mesal projection on the posterior margin of sternum VIII is pointed in Leucotrichia dianeaeand rounded in Leucotrichia tapantia. The rugose ventral surface of the apex of the mesoventral process on sternum VII separates Leucotrichia dianeaefrom all 3 of the other species.  Description. Male. Length of forewing 3.4-4.1 mm (n=10). Head unmodified, with 3 ocelli; antennae unmodified. Dorsum of head dark brown with yellow setae; thorax dark brown with dark brown and yellow setae dorsally, brown ventrally; leg segments with brown setae. Forewings covered with fine yellow setae with dark brown setae at edges and apex. Genitalia. Abdominal sternum VII with pointed, rugose mesoventral process with small basal ridge. Sternum VIII lateral projection elongate, extending dorsad, apex bearing tuft of prominent setae (Fig. 15B), in ventral view with posterior margin concave with small, pointed mesal projection (Fig. 15D). Segment IX anterolateral margin convex, posterolateral margin irregular; in dorsal view anterior margin concave, posterior margin straight. Tergum xwith dorsal sclerite slender; ventral sclerite semielliptic with tridentate posterior margin; membranous apex subquadrate. Subgenital plate with dorsal arm digitate; ventral arm slender, arched mesally, apex acute, in ventral view oblong. Inferior appendage broadest basally, apex digitate, bearing single dorsal spine; in ventral view with basal projection on outer margin and emargination on inner margin. Phallus apex bearing pair of internal apodemes, pair of broad mesolateral membranous lobes, apex divided into pair of lateral lobes. Holotype male: COSTA RICA: Cartago, Reserva Tapanti, waterfall, ca. 1km (road) NW tunnel, 9.69°N, 83.76°W, 2-3.viii.1990, el. 1600 m, Holzenthal, Blahnik, and Munoz(UMSP000201649) (UMSP). Paratypes: same data as holotype, 9 males (UMSP); Cartago, Reserva Tapanti, waterfall, ca. 1km (road) NW tunnel, 9.69°N, 83.76°W, 2-3.viii.1990, el. 1600m, Holzenthal, Blahnik, and Munoz, 1 male (in alcohol) (UMSP); Cartago, Reserva Tapanti, waterfall, ca. 1 km (road) NW tunnel, 9.69°N, 83.76°W, 10.vi.1988, el. 1600m, C.M. and O.S. Flint and R.W. Holzenthal, 1 male (NMNH).  Etymology. Named in honor of R. E. Thomson'smother, Diane Thomson, who has always been supportive of her daughter'sentomological inclinations.