DIOPTIDAE, Introduction; PHAEOCHLAENA. By Dr. Martin Heeing. 
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Dioptidae. 
There is probably no family that opposed such great difficulties to the specialists of former times, as the 
Dioptidae did. Their exterior very easily led to mistake them for others, and it is therefore not to be wondered 
at that the members of this group of lepidoptera were listed in the most diverse families. Some of them have 
been described as Arctiids, others as Geometrids, and others again in Syntomidid genera. Some species were 
even placed to the Psychids, such as Phryganidia. Later on the Dioptids were comprised with the Geometrids 
of the allies of Cyllopoda in the Cyllopodids. It was only in 1918, when Prout (Novit. Zoolog. 25, p. 395 seq.) 
undertook a thorough revision, in which a table for ascertaining the genera was given and all the species were 
cataloguised; we have, on the whole, followed Prout’s revision in the present work. 
If we regard the various forms of the Dioptidae, we find resemblances to the most diverse families. 
Phaeochlaena and Myonia, by their blackish-yellow species, recall Gyllcpcda; Myonia cingulina exhibits a 
striking resemblance with the Syntomidid Microgiton sulmacula Wkr. (36 1), -while other species of the genera 
resemble Pericopids and Heliconiids. Myonia basivitta resembles the Arctiid Euryptidia basivitta (36 1); the 
lustrous blue species with hyaline areas are like corresponding Syntomidids ( Agyrta and others), Tithraustes 
and Polypoetes look like snail Geometrids, Phanoptis is hardly discernible from the Geometric! Locha\ the species 
of Dioptis so much resemble the Dhomiinae that Bates was led to his theory of mimicry; the same design of 
marking and colouring is also exhibited by the Pericopine genus Hyalurga ; Scea has images among the Pyralidae 
and Pericopinae, and Sagaris among the Agaristidcie. The species of different genera also resemble each other, 
as for instance species of Myonia appear in the exterior of Josm-species. 
All the Dioptidae are neotropical except the Californian Phryganidia californica. A great part of the 
species, at least those with bright colours, seenr to fly in the daytime. A striking fact is the prevalence of the 
blackish-yellow colourings. As to the larvae, little has become known; that of Phaeochlaena gyon F. was 
described more minutely. It lives on Aristolochia lactea and is slender, with an oblique, cordiform head, light 
yellow, with three red dorsal stripes and a red spot on the last segment. Four pair of normal ventral feet are 
present, the hind feet are, as in the larvae of our pussmoth ( Harpyia vinula), transformed into two projecting 
anal appendages. The pupa is spun together between two leaves or in an inverted leaf; it is reddish-grey with 
darker spots. The structure of the larva evinces that the Dioptidae have nothing to do with the Geometridae, 
but are to be placed to the allies of the Notodontidae or Drepanidae. 
As the members of the family are often extremely similar to the representatives of other families, some 
principal differences are to be pointed out here. All the Dioptidae lack the analis (vein 1 c) in both wings, by 
which mark they can be separated from similar Pyralidae', in the latter, moreover, mostly the subcosta (vein 8) 
of the hindwing is fused with the anterior edge of the cell. The 2nd median vein is situated midway between 
the 3 rd and 1st median veins, or nearer to the 1st. In similar Pericopidae, Syntornidae etc. the 2nd median 
vein is nearer to the 3rd. Most of the forms, however, resemble Geometridae ; but in the latter there is at the 
base of the abdomen a large, laterally open tympanal organ which lacks the Dioptidae-, in the latter, moreover, 
the subcosta as far as the base is almost parallel to the anterior edge of the cell in the hinclwing, whilst in the 
Geometrids it makes yet very close at the base a large bend which is anteriorly convex. The hind tibiae 
always have two pair of spurs, the tongue and frenulum are well developed. 
r 1. Genus: P]i«lcoclll«lCll<i Hbn. (Campylona Mschlr., Neolaurona Drc., Clastognatha Fldr.). 
In the forewing the 2nd radial vein rises from the cell; the 1 st cubital vein likewise rises from the 
cell; in the hindwing the 1st cubital vein and the 3rd median vein rise separately. The species are all marked 
black and yellow or brown. 
Ph. gyon F. (68 a). Wings dark brown, basal area indistinct, a discal band more distinct and the (/l/ul i, 
veins partly yellow in the forewing, a subapical spot yellow or white. Hindwing with a yellow central area. 
—- In the typical gyon F. (= tendinosa Hbn., remota Wkr., obtecta Mschlr.) the discal band is rather distinct, 
the subapical spot white. — The form ochropliarses Prt. has broader yellow markings, the discal band terminates ochropha- 
posteriorly in a clear yellow spot. — In dorsistriga Strd. there is in the forewing but 1 subapical spot and a nes. 
broad light stripe on the analis. Guiana, Colombia, Amazons, Peru, Mexico, Honduras. — In lanipra Prt. only d° rs isiriga. 
the costal-marginal spot of the discal band is distinct and rounded off; the subapical spot is yellow. South ' " l "' ' 
Brazil, Paraguay, Uruguay, a similarly coloured specimen also from Honduras. — fucata Prt. is on the hindwing facata. 
above and on both wings beneath orange instead of yellow; Rio Uruguaya, Brazil. 
Ph. solilucis Btlr. (68 a). Yellow, in the forewing the costa as far as the centre, the lrind-margin, and solilucis. 
a transverse band as well as the apical part are black, the latter with a yellow subapical spot. Hindwing yellow, 
distal margin and apex black. — In subintrusa Warr. the black discal band extends into the following yellow suiintrusa. 
transverse band; — in perintrusa Prt. the latter is divided into two yellow spots, in confingens Warr. (— aurata ■perintrusa. 
Warr.) the posterior margin of the forewing is yellow, otherwise like solilucis. Panama, Brazil, Peru; at contingens. 
the latter patria contingens seems to predominate, 
