FUMEA. By Dr. E. Wehrli. 
223 
gives the wing expanse as 19.5 mm (as ledereriella), Heylaerts even as 20—22 mm, whilst Rebel mentions 
21 mm for apistella. The original specimens of Lederer’s proximo, , which are before me, measure 19.5 mm 
and another specimen 18.5 mm, varying therefore only slightly from my apistella from the Apennines; also the 
wing contour shows scarcely discernible differences. Just as little does the dark grey-brown colouration of one 
of the specimens, whilst the other is paler brownish. The brown colour would appear to be due to the age 
of the specimen, because a fresh one from Minussinsk has an almost pure dark grey colour without the 
distinct brownish sheen. Actually apistella has longer pectinations, the proportion is 1.8 : 1.4 to 1.5, also the 
shaft is thicker (5 : 3 ) than in any proxima, a characteristic which enables one to distinguish the species easily. 
P. pectinella F. (Vol. 2 , p. 366, pi. 55 h). The descriptions hitherto given in literature of the larvae of pectinella. 
this species, all refer to the similar larva of Oreopsyche muscella, which has been offered owing to a mistake by 
hungarian dealers. We owe the description of the genuine pectinella larvae to Rebel. They were discovered 
by Robert Spitz. They are similar to the larva of bombycella, smaller, paler inclining to violet-grey, not 
blackish brown as the latter and their subdivided double rows of dorsal pads, as well as the 3 rows of lateral 
protuberances are much less prominent than in bombycella. When prepared the pectinella larva measures 
15 mm. — The species is recorded by Vorbrodt as occuring in Switzerland in Maroggia, Tessin, Martigny, 
Stalden in Valais, Simplon; Fahrweid in Zurich. Dannehl mentions also the South Tyrol. 
c. Subfamily: Fumeinae. 
23. Genus: Fumea Haw. (Masonia Tutt). 
Masonia was based essentially on a slightly larger number of segments to antennae, 20—24, interme¬ 
diary position of the spine on foretibiae, • 65—71, and insignificant, scarcely constant reduction in the seg¬ 
ments of the tarsi of $, differences, which in view of Burrows’ authenticated inconstancy of these Fumea 
species, can claim neither generic, subgeneric nor even specific importance. The <$ genitalia are, according 
to Burrows, completely identical. Tutt classified the species crassiorella Bui. and subflavella Mill, to Masonia, 
as well as a few forms from England, which are however as yet not sufficiently definitely established. 
Tutt and Chapman, in creating their species and Genera, have paid especial attention, apart 
from the number of segments of antennae, to the relative length of the spine of the foretibiae and the posi¬ 
tion of the spine on same. Tutt expresses by means of a numerical index, the proportion of the length of the 
foretibia from the juncture of the spine to the extremity of the tibia, as compared to the length of the 
spine, or according to Burrows to the over-all length of the tibia, crassiorella had an index • 65 71, casta 
. 77 _-81. According to Burrows’ measurements of Chapman’s specimens, these index numbers form a 
continuous series, so that no definite limit can be fixed for any one species. The variations in measurements 
differ by at least -02; in the more highly developed Psychidae, the scope of variation in one and the same 
species can be up to • 05, for instance in Ps. bombycella and R. majorella. Reliable measurements can only 
be made by means of microscopic slides and the same applies to the counting of the segments of the antennae. 
An error in measurement of 0.01mm would suffice to transplant a species from one to another denomination 
and according to Burrows, even to another Genus. 
In the Fumeinae, as far as I can ascertain, no exact measurements of the spine or of the count of 
the segments of the antennae have been made over a large quantity of material, so as to enable one to 
definitely fix the degree of variability in the same species or their relationship to the size of the insect and 
other factors. It would appear therefore to be incongruous to establish new species and denominate forms, 
on the basis of minute differences in the index numbers of a few specimens, without there being any other 
fundamental differences. This more especially when one considers the difficulty in taking exact measurements. 
For instance in this regard the measurements taken by two authors of the same material, vary quite con¬ 
siderably. Burrows’ measurements of Chapman’s material differ materially, for instance m betulma from 
• 04 downwards to • 09 upwards, thus an overall difference of • 13; thereby producing index numbers which 
overlap into two of Tutt’s Genera! In germanica the difference amounts to • 07, thus going over into casta 
w ith • 77 _81, in hibernicella ■ 10 , in mitfordella Ghapm. ■ 06 etc. Through the interloping and overlapping 
of the indices given for these species, such denominations, which are solely based on these index numbers, 
must be dropped, unless of course subsequent investigation of large series, proves that there are other essential 
differences. — Naturally the relative length of the spine is a contributory factor m establishing the subdivi¬ 
sion into groups. 
A. Wings without reticulation, cellula in t r u s a absent, pectinations of anten¬ 
nae with scales ( Fumea ). 
F. casta Pall. (Vol. 2, p. 368, pi. 55 i) (= bowerella Cliapm., minor Glxapm., nitidella Hbn., intermediella casta . 
Brd., all based on the number of segments of antennae, varying to the extent of one segment and other 
minute differences in size). Chapman has separated — scotica Cliapm. (described as a separate species) scotica . 
from Rannoch and Sutherlandshire, Scotland. It is a robust form, in size of crassiorella Brd,, or even larger 
