P,M. t. VIII. 1913. HEPIALUS. By R. Pfitzxer. 433 



26. Family: Hepialitlae. 



The Hepialids are a subdivision of the Micropterygina, which represent the oldest type of Lepido- 

 ptera now existing. Together with the Micro pterygidae they form the group " Jugatae" which Comstock (Ithaca, 

 U. S. A.) places in contradistinction to the "Frenatae". This type is distinguished from all other families of 

 Lepidoptera, the Frenatae, which possess a frenulum, by the lobe (jugum) which extends from the base of the 

 forewing to the costa of the hindwing over the gap between the two wings so characteristic of the Hepialids. 

 In the "Jugatae" which is the oldest still existing group of Lepidoptera the phylogenetic derivation of the Le- 

 pidoptera from the Trichoptera (Phryganids, caddis-flies) is distinctly recognisable, for not only is their body 

 hairy, but there are hairs on the membrane of the wing, which is never the case in the Frenatae. Moreover, 

 it has been shown by Quail's publications with their interesting illustrations that the structure of the wing- 

 scales of the Hepialidae is absolutely unique in that it illustrates the modification of hairs into scales. The 

 venation presents further points for comparison. The oldest of all forms of Micropterygidae, Palaemicra mlco- 

 phanes from New Zealand, equal m antiquity to the Moa, Kiwi and other forms of life of that country, is in its 

 structure so closely allied to the genus Rhyacophila of the Trichoptera that it might almost be considered a link 

 between the two orders of insects. The following characteristics especially betray the great age of the Hepiahd 

 type, which according to Packard goes back to the Jurassic Epoch. The most striking distinctions of the well- 

 known mimistakable imago, apart from the remarkably long abdomen, the long narrow and rotmded wings 

 and the "gap" already mentioned, are the antemiae which usually are ver^^ short and scarcely visible, and the 

 reduced or obsolete mouth-parts, in contradistinction to which the shaggy legs are strongly developed. The 

 long slender larvae have 16 legs and are naked, with a glossy head and hairy warts, livmg miderground on 

 roots or inside trees. The pupae also present a primitive type: they are elongate, mobile, with free hmbs, spines 

 on the abdominal segments (the piipa is the more rigid and has the less number of mobile joints the higher 

 the species stands in the phylogenetic development of the Lepidoptera). 



In the habits of the imagmes there is also much that is peculiar to this family. The Hepiahds are on the 

 wing at dusk, the flight of the (J being often of that well-known pendulating kind which can be observed in 

 many other orders of insects, e. g. the Ephemerids. The $? go in search of the ^(^, and then fly along over the 

 grass to drop their eggs. Apart from the short time of activity at dusk, scarcelj' lasting haK an hour, the He- 

 pialids are extremely lazy and cannot be induced to fly by any means. Many species also come to the lamp. 

 The distribution of the Hepialids is very general, extendmg as far as the Ai'ctic regions and up to the snow-line 

 of the mountains. They prefer mountains to plains, and damp locahties to dry ones. In Europe the most interesting 

 forms of Hepialids are found m the British Isles. It seems as though the known species, of which there are scar- 

 cely more than 200, are the remains of a former magnificent Hepialid or Micropterygid fauna, Avhich, together 

 with the bizarre dragons among the Saurians and relatively just as gigantic, inhabited the mist-laden moors 

 and gloomy fern-woods of a prehistoric epoch. Zelotypia stacii, an imposmg species (expanse up to 24 cm) 

 and the South American Phassus gigantetis look like relics from former times. According to Meyeick the centre 

 of distribution of the family is to be found in the Indo- Australian region, especially New Guinea. Who knows 

 whether we may not one day be surprised by a new gigantic form of Hepialidae from the unknoMTi interior 

 of this island, whence we have already received the largest known forms of Ornithoptera and Saturniidae. 



From the Palearctic, and especially the European, Hepialids we only get a slight idea of the size 

 and beauty of this highly interesting family. The number of species is small. In Europe proper there are nine 

 or ten forms, while the same number of species occurs alone in New Zealand and three or four times as many 

 in Australia. The latter continent probably contauas more Hepialids than the entire Palearctic Region even 

 with its new extended boundaries. 



The followmg Hepialid genera occur m the Palearctic Region: HepialusF., Palpifer Hamps., Hepialiscus 

 Hamps., Gorgopis Hhn., Phassus Walk. 



1. Genus: Hepialiis F. 



Head and thorax clothed with woolly hau\ Antennae shorter than thorax; eyes naked, no ocelli; palpi 

 minute; no tongue, but two round knobs uistead. Both wings with 12 veins and a cellule m cell between vems 4 



II 55 



