Collin: A black species with a silvery patch on the vertex and each side of the front of the frons. Thorax with notopleural depression silvery, and pleurae with silvery patches. Palpi black, prominent and fiat. Ocellar bristles small; two pairs of front-orbital bristles; only one (outer) pair of vertical bristles. Frons slightly narrower in male than in female, but not with eyes almost touching as stated by Hendel. Four scutellar, no sternopleural, two postalar, and one supra-alar, bristles the anterior supra-alar bristle mentioned by Hendel not present. Wings with upcurved discal vein as in other members of the family. About 6 mm,
Base of tarsomere 1 of hind tarsus very slightly projecting ventrally; male with small stout black setae on hind trochanter and posterior base of hind femur. Postocellar bristles strong, at least half as long as upper orbital seta; one dorsocentral and three orbital setae present (from key, Sumner)
Many detailed figures in Roháček, 1998
Europe: Countries (published), online at Fauna Europaea, Occurrences at GBIF
UK: Recording Scheme map of occurrences 2016 (verified.) Online (NBN Atlas) via Easy maps or Interactive Atlas
Séguy, 1934: Male - Yeux à facettes antérieures un peu dilatées. Espace interoculaire subégal à la longueur de l'antenne ; bande médiane frontale triangulaire, la pointe antérieure d'un noir velouté; une plaque blanche derrière le triangle ocellaire. Gênes très étroites, d'un blanc d'argent comme les orbites et les joues. Chète antennaire cilié. Corps légèrement luisant, noir ou brun roux; côtés du mésonotum et pleures couverts d'une épaisse prui- nosité argentée; macrochètes faibles. Pattes jaunes : tarses brunis. Balan ciers blancs. Ailes vitreuses fortement irisées. Cuilleron thoracique en lanière étroite ; cuilleron alaire arrondi, longuement cilié à la marge. Abdomen étroit. Appareil copulateur épais, replié sous le ventre; pénis très allongé.
Female: abdomen ovalaire; oviducte long.
Long. : 6-8 mm.
Roháček, 1998: Adults of Tanypeza longimana occur on low vegetation in humid deciduous woods, usually along brooks and rivers in lowlands (e.g., in floodplain forests) and sub montane areas. Larvae are saprophagous (as Foote 1970 demonstrated by larvae reared on decaying watermelon rind) and probably live in rotting wood (Chandler 1975) or other plant detritus under natural conditions. Foote (1970) reared larvae from eggs laid by a gravid female in moist peat moss in a breeding jar. First instar larvae hatched after 3-5 days. A number of lar vae reached 3rd instar stage but none of them formed puparium. Duration of particular instars was not recorded.
Roháček, 2016 : This is the only representative of the family Tanypezidae in the Palaearctic
Region (Roháček 1998; Lonsdale 2013). Its biology is insufficiently known, inasmuch as the larvae have hitherto not been found in their natural breeding substrate. It was speculated that larvae may be saproxylic, developing in rotting wood (Chandler 1975) because adults can often been seen on vegetation near decaying stumps or dead fallen trunks (Chandler /l. c./ found them among vegetation growing over a rotten willow). This fact seems to be also indicated by specimens caught by means of pyramidal trap (see material examined) under which a lot of rotting wood was installed. Larvae of T. longimana were reared by Foote (1970) on decaying watermelon rind from eggs laid by a gravid female but they failed to pupariate, hence this alternate substrate was probably unsuitable to complete their life history. Foote (l. c.) described only larval instars obtained from the above rearing experiment; the puparium remains unknown. Adults of both sexes often walk on leaves of low vegetation, where also mating can be seen. Margins of moist deciduous or mixed forests, and particularly forested banks of rivers and brooks at lower altitudes seem to be the preferred habitats of this species in Central Europe (Roháček 1998, material examined). Adults were found from 28 May to 6 August in the Czech Republic and Slovakia, while the majority of records are from June