Hydririni

Adult Hydririni are narrow- to broad-winged moths. Many species exhibit an inconspicuous wing pattern of brown and ochre colours, whereas species like Choristostigma roseopennalis (Hulst, 1886)^[2] can be rather colourful.

The tribe is characterised by two synapomorphies: the female genitalia have an appendix bursae on the corpus bursae (as found in Pyraustinae), and the male genitalia of most Hydririni exhibit one or more hair scale patches on the central anterior edge of the abdominal sternite 8. Apart from this, the morphology of the genitalia is rather heterogeneous: in the male genitalia, the valves are slender to broad, and the uncus and gnathos range from well-developed to reduced. The genera Choristostigma, Hydriris, Nehydriris and Rhectothyris have lobar processes with a field of long, thin hair-pencils on the dorsolateral tegumen as well as a phallus with a long caecum and a straight or hooked cornutus.

In the female genitalia, two general types of signa are observed in the corpus bursae: the "ediacaroid" signum (sensu Mally et al. 2019) has the transverse axis more or less reduced, and the signum is elongate and zipper-shaped to nearly circular; the second type is formed by a circle of radiating spines. In Ommatospila, both signum types occur together.^[3]

Hydririni are one of the four tribes that form the paraphyletic "non-euspilomeline" group, with the "euspilomeline" clade nested within. The "non-euspilomeline" tribes are characterised by plesiomorphic characters shared with the sister group of Spilomelinae, the Pyraustinae. These plesiomorphic characters include the absence of a longitudinal sclerotized strip on the pleural membranes of the male abdominal segment 8, a straight or concave costa of the valves and an evenly sclerotized phallus apodeme in the male genitalia, as well as the "ediacaroid" signum and an appendix bursae in the female genitalia.

The morphology and chaetotaxy of Hydririni larvae has not been scientifically described.

Recorded food plants of Hydririni larvae are predominantly Sapindaceae: Allophylus psilospermus, A. racemosus, Paullinia bracteosa, P. costaricensis, P. faginea, P. fuscescens, P. grandifolia, P. turbacensis, Serjania atrolineata, S. mexicana, S. rhombea, S. schiedeana, S. valerioi, and Urvilea ulmacea.^[4] A single case of feeding on the Fabaceae, Senna obtusifolia is recorded for a Costa Rican specimen of Lamprosema,^[4] and the young larvae of Hydriris ornatalis feed on the leaf undersides of Ipomoea batatas (Convolvulaceae) and related plants, whereas older larval instars skeletonize the leaves.^[5]