Philibaetis Kaltenbach & Gattolliat gen. nov. Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

Type species.

Philibaetis luzonensis ( Müller-Liebenau, 1982) comb. nov., by present designation.

Species included.

Philibaetis realonae ( Müller-Liebenau, 1982) comb. nov.

Diagnosis.

Larva. This new genus is distinguished by a combination of the following characters: A) body elongate and slender, head clearly hypognathous (Fig. 5); B) bases of antennae not close to each other, without carina between them (Figs 5c, 8c); C) labrum rectangular, on dorsal surface with submarginal row of long, simple setae (Fig. 1a); ventrally on lateral margins long, simple, spine-like setae, on anterolateral margins long, feathered setae and medially long, bifid setae and a partial, submarginal row of lanceolate setae (Figs 1b-f, 6a, b); D) right mandible with blade-like incisor, stick-like, apically denticulate prostheca and dorsally mediolateral patch of long, spine-like setae (Fig. 1g, h, l); E) left mandible with blade-like incisor, slender prostheca apically denticulate and with comb-shaped structure; tuft of long, partly-branched setae at base of subtriangular process; dorsally mediolateral patch of long, spine-like setae (Fig. 1i-k, m); F) hypopharynx with a medial tuft of stout setae and anterolaterally two smaller tufts of stout setae (Fig. 2a); G) galea-lacinia with three denti-setae, distal denti-seta tooth-like and directed against canines, middle and proximal denti-setae slender, bifid and pectinate; maxillary palp 2-segmented, apex of segment II constricted (Fig. 2b); H) glossae basally broad, narrowing towards apex, shorter than paraglossae, apically and on both margins with long, spine-like setae; paraglossae truncate in distal part, one stout, bifurcate seta in posterolateral area; labial palps segment II without protuberance (Fig. 2d, e); I) fore femur apically with stout setae both on anterior and posterior side, femoral patch absent; claw robust and pointed, with one row of denticles and 2-3 long subapical setae on posterior side and one short, fine, subapical seta on anterior side (Figs 3a-c, 11); J) paraproct with patch of notched scales (Fig. 4e, f); K) protogonostyli under larval cuticle folded in the Labiobaetis type (Fig. 10).

Imagines.

Unknown.

Etymology.

Philibaetis is an arbitrary combination of letters with allusion to the Philippines, where the genus occurs and to the genus Baetis . The latter is with reference to the superficial similarities between both genera and the fact that the species of Philibaetis gen. nov. were up to now assigned to Baetis . Gender is masculine.

Description.

Larva. (Figs 1 - 11).

Body. Elongate and slender, head hypognathous (Fig. 5).

Head. Antenna (Figs 3d, 5c, 8c). More than 2 × longer than head length, bases of antennae not close to each other, without carina between them (Figs 5c, 8c).

Labrum (Figs 1a-f, 6a, b). Rectangular, wider than long; on dorsal surface with submarginal row of long, simple setae; ventrally on lateral margin long, simple, spine-like setae, on anterolateral margin long, feathered setae and medially long, bifid setae and a partial, submarginal row of lanceolate setae.

Right mandible (Fig. 1g, h, l). Incisor and kinetodontium fused, incisor blade-like, kinetodontium with denticles; inner margin of innermost denticle of kinetodontium without row of thin setae; prostheca stick-like, apically denticulate; dorsally with mediolateral patch of long, spine-like setae.

Left mandible (Fig. 1i-k, m). Incisor and kinetodontium fused, incisor blade-like, kinetodontium with denticles; prostheca apically denticulate and with comb-shaped structure; with tuft of long, partly-branched setae at base of subtriangular process; dorsally with mediolateral patch of long, spine-like setae.

Hypopharynx (Fig. 2a). With medial tuft of stout setae and anterolaterally two smaller tufts of stout setae.

Maxilla (Fig. 2b, c). Apically with three stout canines and three denti-setae; distal denti-seta tooth-like, with opposite direction to canines, other denti-setae slender, bifid and pectinate; maxillary palp with two segments.

Labium (Fig. 2d, e). Glossae basally broad, narrowing towards apex, shorter than paraglossae; apically and on both margins with long, spine-like setae; paraglossae truncate in distal part, on apex with three rows of long, robust, distally-pectinate setae and one stout, bifurcate seta in posterolateral area; labial palps segment II without protuberance, dorsally with row of spine-like setae near outer lateral margin.

Thorax. Hind protoptera (Fig. 4g). Absent.

Foreleg (Fig. 3a-c). Femur with dense row of curved, spine-like setae on dorsal margin, on apex short, stout setae on anterior and posterior side; femoral patch absent; tibia with patellotibial suture, dorsal margin with row of medium, clavate setae; claw robust and pointed, with one row of denticles, 2-3 long subapical setae on posterior side and one short, thin subapical seta on anterior side.

Abdomen. Gills (Figs 4a-d). Seven pairs of gills on segments I-VII, dorsally orientated. Margin with minute denticles intercalating fine, simple setae.

Paraproct (Figs 4e, f). Without prolongation at posterior margin, with stout, marginal spines; surface with patch of notched scales.

Caudal filaments (Fig. 5a, d). Inner margin of cerci with long, thin setae; paracercus bilaterally with long, thin setae.

Imago.

Unknown.

Distribution

(Fig. 12). Philippines: Luzon.

Redescription