Small to medium-sized larvae, to 4 mm long.
Antenna with 5 segments on a short pedestal with an inner rounded tooth. Antennal ratio around 1.3. Ring organ basal on 1st antennal segment. Seta well developed. Lauterborn organs large, on stems slightly shorter than length of 3rd segment, located opposite on apex of squat 2nd segment. 3rd segment much longer than 2nd. Antennal blade not beyond apex of 3rd segment, accessory blade undescribed. Style not observed.
Labral setae and labral lamellae not described. Pecten epipharyngis 3 distally serrate scales. Premandible with 3 apical, 1 broad inner teeth.
Mandible with pale dorsal tooth, apical tooth and 2 pointed inner teeth dark. Seta subdentalis long, curved, reaching beyond dorsal tooth. Seta interna unobserved. Pecten mandibularis apparently weak with few lamellae.
Mentum with trifid pale median tooth, with outer toothlets variable in size and degree of fusion, 5 pair of laterals, regularly decreasing in size. Ventromental plates close together medially, a little wider than mentum, striae undescribed.
Without tubules. Some claws of posterior parapod with serrate margins.
The generic diagnosis is based upon the larvae of the Neotropical C. friederi, C. ortoni Säwedal and C. riotarumensis (Trivinho-Strixino and Strixino 2000, 2003): larvae of Nearctic species may differ slightly from the above diagnosis. The larvae of Caladomyia are similar to Cladotanytarsus, Tanytarsus and Virgatanytarsus, but can be separated from Holarctic species in all these genera by having a combination of long Lauterborn organ pedicels, two well developed inner teeth on the mandible, three teeth on the premandible, a small, pointed apical tooth on the antennal pedestal and usually some serrate claws of the posterior parapods. However, no larval features or combinations of characters that sufficiently separates Caladomyia from Tanytarsus on a world wide basis. It is possible that Tanytarsus is paraphyletic with respect to Caladomyia and that future phylogenetic analyses will alter the taxonomy of this group.
Larvae of Caladomyia inhabit lakes, reservoirs and ponds. About 20 species are described from the Neotropical Region (Reiff, 2000; Sanseverino and Fittkau, 2007) and at least three undescribed species are known from south and western United States (Texas, Oklahoma and California).