NATURAL AFFINITIES
In the Monographs (1869) Osten Sacken included the genus Dicranoptycha in his tribe (section) Limnobina anomala, or, as it subsequently became known, the Rhamphidini, and still later the Antochini. A recent survey of the immature stages of several Antochine genera has shown that the tribe is merely an artificial grouping based on superficial resemblance of the adult flies. This heterogeneous assemblage includes representatives of at least three other tribes, Dicranoptycha, together with Antocha, Elliptera, Rhamphidia, etc., showing an undeniable affinity with the Limnobiini, whereas Teucholabis, Elephantomyia, etc., show an equally clear relationship with the Eriopterini. Moreover a close phylogenetic relationship with the lowermost subtribes of the Hexatomini (Ularia, Epiphragmaria, etc.), is easily apparent.
Dicranoptycha shows the closest affinities with Antocha and Rhamphidia. The larvæ of these three genera, each of which typifies a division, show the following common characters:
Abdominal segments with basal transverse creeping welts or areas of microscopic points. The massive compact head-capsule with the præfrontal sclerite large, distinct, the externo-lateral plates large, mussel-shaped and very thin. The mentum is not completely divided medially. The maxillæ are large and of primitive structure, the cardines and stipites distinct, the two distal lobes large, subequal in size, covered with hairs and bearing sensory organs. Mandibles with one or more dorsal and two or more ventral teeth in addition to the apical point.
The differences between these allied divisions are best indicated by a key.
LARVAE
1. Spiracular disk with only the two long ventral lobes remaining; spiracles lacking or vestigial; abdominal segments with both dorsal and ventral welts; strictly aquatic.Antocharia.
Spiracular disk surrounded by four or five short lobes; spiracles large and functional; abdominal segments with ventral welts only (except the dorsum of segment eight); terrestrial or semiaquatic.
2. Body moderately elongated and covered with a long dark pubescence; spiracular disk squarely truncated, surrounded by five subequal stout lobes; mentum with five subequal teeth, the lateral one of either side not conspicuously reduced.Rhamphidaria.
Body very long and slender, glabrous; spiracular disk obliquely truncated, surrounded by four slender naked lobes; mentum with three subequal primary teeth and a much reduced lateral tooth on either side.Dicranoptycharia.
PUPAE
1. Pronotal breathing-horns branched; aquatic.Antocharia.
Pronotal breathing-horns not branched; semiaquatic or terrestrial.
2. Pronotal breathing-horns distinct, elongate-cylindrical.Rhamphidaria.
Pronotal breathing-horns apparently lacking, microscopic.Dicranoptycharia.