Head, thorax, wings (Figs 4C, 4D, 5E, 5F). Same as described for male (Tauber 2007, as Leucochrysa bullata).

Female abdomen (Figs 1C, 2, 3). Segments 1–7 long, slender; tergites shallow [ratio length : width = 8.6 (T5), 7.5 (T6), 4.0 (T7)], with slightly rounded margins, with brown circular spot mesally; T8 shorter, rounded, without brown spot. Sternites deep [ratio length : width = 1.5 (S5), 1.0 (S6), 1.4 (S7)], with dorsal margins slightly depressed (concave) mesally; tergites, sclerites with numerous, long, thin setae, dense microsetae, without microtholi. Pleural region with microsetae, P7 with long, thin setae; spiracles small, simple, with unenlarged atria.

Female genitalia. Callus cerci round to slightly oval, 0.10–0.15 mm in diameter, with 19–21 relatively thin trichobothria (longest ~0.13 mm long); cupuliform bases of variable diameter. Tergite 9 + ectoproct rounded, fused dorsally, blunt posteriorly, elongate, ventral section on each side enlarged into pair of bulbous lobes extending well below gonapophyses laterales; enlargement covered with dense, stout, upward-curving setae. Gonapophysis lateralis not large, occupying approximately one-half of posterior margin of abdomen; surface covered with robust, stout setae, especially on ventral half; interior membranous area not greatly expanded. Colleterial gland transparent, delicate, ovoid, small, mostly within gonapophyses laterales and T9+ect, not extending anteriorly much beyond bursa, but with numerous elongate accessory glands attached distally, with transparent, membranous tubule connecting to small reservoir; transverse sclerification short, narrow, receiving short duct from reservoir. Entire genital structure small, not much larger than subgenitale. Bursa copulatrix membranous, broad basally (near subgenitale), tapering and extending slightly into region above S7, folded dorsally, with slight longitudinal depression dorsally, connected ventrally to spermatheca via elongate dorsal slit on spermathecal velum and bursal duct at proximal tip of velum. Bursal duct very short, slender. Bursal glands not seen. Spermatheca doughnut shaped, tucked within distal end of bursa, with small, sail-like velum dorsally, small, V-shaped invagination ventrally. Spermathecal duct attached dorsally to distal end of spermatheca, short, sclerotized, extending into and out of subgenitale, with ~three curves, closely attached to membranes of bursa and subgenitale; terminus with long, dense setae. Subgenitale broad basally, rounded distally, nestled between ventral lobes of ectoproct, narrow in lateral view, with shallow ventral fold at attachment to S7, slightly deeper fold above, terminal process flat, long, extending almost full length of subgenitale, with pair of lobes at base, shallow crumena at rounded tip; membrane above subgenitale with crescent-shaped, lightly sclerotized lamellae.

Holotype (ZMCU) and a second female specimen (MCZ), with labels reading: [1] “El Campamiento Col. P?r?n? [“?” mine] PERU 1 July ’20”, [2] “Cornell Univ. Expedition Lot 569”, [3] “Leucochrysa (or Nodita) risi Esb-Petersen 1932 det. P.Adams 1974”. The locality data appear to refer to the Expedition’s Camp at Perené in the province of Chanchamayo, Junin, Peru, elevation 696 m (Cornell University Insect Collection Voucher Lot Series, Lot 569).

Currently, this species is known only from three regions of Peru: Junin (~650 m) (new record), Pasco (~800 m) (Esben-Petersen 1933), and Madre de Dios (250 m) (Tauber 2007).

The genus Santocellus was described on the basis of a distinctive suite of larval and adult (male and female) character states. However, Santocellus risi (as bullata) was included in the genus only on the basis of its male characteristics (Tauber et al. 2008); both the female and the larvae were unknown when the genus was described. We now know that, in addition to the striking pustulate wings and unusual body markings that typify the species, Santocellus risi females have abdominal characteristics that are distinctive among the Leucochrysini (setose, bulbous lobes on the ventral margins of the ectoproct and unique, stout, curved setae). However, they also share a large set of female features with their congeners, Santocellus atlanticis and Santocellus riodoce: (1) a round, pillbox-shaped spermatheca with a shallow invagination; (2) a relatively short, lightly sclerotized spermathecal duct; (3) spermatheca with a sail-like velum that opens via a slit to a short bursal duct; (4) spermathecal/bursal complex relatively small, spermatheca nestled below the bursa copulatrix; (5) gonapophyses laterales relatively round and short; (6) colleterial gland bulbous, delicate, transparent, and with several elongate tubules attached to the distal end; (7) subgenitale with two, small to medium-sized, basal folds (at the attachment to the seventh sternite), with a ventral process that is elongate and flat, has a rounded distal margin, rounded lobes basally, and a shallow crumena. The expression of this set of features by the female of Santocellus risi provides new support for keeping the genus Santocellus separate from Leucochrysa, and it offers strong evidence for retaining the species within the genus.