Lieftinck (1975) erected Caledargiolestes janiceae based on just one semi- adult male collected by Mrs. Janice G. Peters, a member of the Florida Agricultural and Mechanical University Expedition in 1972 (FAMU expedition), in a stream on Mont Pouédihi. Winstanley (1984) collected a female C. janiceae during an expedition supported by the New Zealand Entomological Society, but provided no information on the precise capture locality, habitat, or where this specimen was deposited. Davies (2002) published an updated list of New Caledonian Odonata, recording C. janiceae as “rarely seen, perhaps early season”. He stated that to his knowledge there was one female in the Cambridge University Museum of Zoology (CUMZ) (United Kingdom) collections, dated 18 February 1983, collected in the same area as the holotype “in southern New Caledonia, between Nouméa and Yaté”, which is presumably the individual collected by Winstanley (1984). Daniel Grand, member of the Société Odonatologique de France and Société Entomologique de France, unsuccessfully searched for the species on several field trips (January–February 2004; January 2010; January–March 2011; November 2011) visiting areas around the type locality of C. janiceae (Grand et al. 2014, 2018, 2019). Grand et al. (2019) therefore classified C. janiceae as “Critically endangered”. Lacking a described female, this species is distinguished in an identification key and its amendment (Grand et al. 2014, 2018) from its only congener, C. uniseries (Ris, 1915), solely based on male terminal abdominal appendages: C. uniseries superior appendages have “a deep angled notch toward the tip”, whereas in C. janiceae these have a “knob-like process (not notch!) toward the tip”.

Despite further searching, this species was only rediscovered in early 2022 with one female and two males (immature and mature) collected. Stenger et al. 2024 describe a recently collected female C. janiceae and redescribe the male at different stages of maturity based on in situ living photographs and examination of the specimens. Here are the description:

Description of female Caledargiolestes janiceae

Head. Labium dark brown, submentum and squamae paler to yellowish; median emargination of midlobe oval, its depth about one-third of total lobe length; entire surface of labium clothed with long whitish hairs. Postclypeus dark brown, labrum blue with basal infuscation, especially medially and at corners, outer face mandibles paler blue. Frons anteriorly pruinescent light blue, whole surface clothed with very long raised white hairs, a few of these also in front of the lateral ocelli; the blue antefrons mask forms a “peak” on each side extending towards the base of the antennae. Genae with broad pale blue marking to just beyond level of antennal sockets, which then tapers very thinly along eye margin to level of median ocellus. Antenna sockets brown in front, antennae brownish black, pedicel reddish brown. Head bronze-black with brownish spots between the base of the antennae and the median ocellus. Median ocellus light grey to grey, and lateral ocellus darker.

Thorax. Largely coppery brown to brown with some pale yellow marking. Prothorax light coppery brown above with small darker smudges, dark brown laterally. Mesepisternum strong coppery brown, a little darker than pronotum. Mesepimeron dark brown. Small elongated pale yellow streak beginning two-thirds along mesopleural suture and terminating at fossa. Mesepimeron dark brown with small pale yellow wedge shape ventrally between mesepimeron and metepisternum, on the interpleural suture from the metathoracic spiracle to the middle of the interpleural suture. Metepisternum much paler brown with pale yellow patch near top and thin dark brown line along suture with metepimeron. Metepimeron dark brown with two pale yellow bands, one in the metapleural suture interrupted dorsally and ventrally, and another broad yellow band on hind margin of metepimeron. Mesinfraepisternum dark brown, metinfraepisternum mainly dark brown with yellow corner posteriorly. Legs generally dark brown becoming darker to almost black at the tarsi and claws; all coxae bi-coloured with coppery brown anterior and yellow posterior faces.

Wings. Hyaline, venation brown/black. Pterostigma brownish with brown/black venation, rhomboid. Arculus at Ax2.

Abdomen. Dark brown with slightly metallic highlights and pale yellow maculation; small hairs covering S1–10; distal part of S1 raised and convex in profile, dark brown, sides with two yellowish triangular markings covering at least half the sides; S2 blackish brown with diffuse yellow spot at base and middle, meeting in obscure pale area dorsally; S3–7 each having well-defined yellow basal rings and a yellowish median ventral triangle, not meeting dorsally; each segment with narrow apical dark ring. S8–10 darker; S8 with a pair of small light basodorsal spots, the rest unmarked.

Ovipositor and anal appendages. Stylus dark with long erect white hairs. Valves of ovipositor dentate. Cerci pyramidal/triangular.

Measurements (in mm). Total length: 30.4; length of abdomen including cerci: 23.8; fore wing length: 18.7, greatest width of fore wing 4.1; hind wing length: 18.8, greatest width of hind wing 4.2.