lxxxvi Journal of Proceedings.
extinct, we should then have a case of dimorphism. The same thing
was to be seen in our " Clouded-yellow butterfly" (Colias edusa) ; there
were two distinct forms of female, in one of which the ground-colour was
precisely the same as that of the male, while in the other it was much
lighter (ab. helice). Under ordinary circumstances we never found any-
thing intermediate between these two forms, but it happened that one
year—he thought it was 1877—this butterfly was very abundant, and
swarmed all over the country.* Hundreds of intermediate specimens
were then found, and he considered that these were " reversion forms,"
showing that this phenomenon of dimorphism had arisen from simple
variability. On the whole he thought that such varieties as had been
exhibited by Mr. Oldham would be found one of these days, when the
whole of the facts were carefully worked up, to be of very great import-
ance indeed, because the phenomena of dimorphism and polymorphism
were at present inexplicable. This was one more reason for bringing
forward facts bearing on subjects of which they knew so little.
The Secretary stated that he had received from Dr. Cooke a list of
Hymenomycetal Fungi, new to the Forest district, observed in 1882,
being a supplement to the list published in the last volume of the
'Trans-actions' [vol. ii., p. 181]. It recorded 36 species, including
Cortinarius renidens before noticed [ante, p. lxi.] [This list is reserved for
the present for the purpose of including in it the species noted in
1883, &c.—Ed.]
He also read a note from Mr. Reginald W. Christy, who recorded the
capture of a specimen of Colias edusa ♂ on September 22nd, 1882, at a
place called Chalk End, in the parish of Roxwell, being the first speci-
men he had seen in Essex since the famous year 1877. On October 1st
he saw two other specimens (male and female) near Writtle.
Mr. W. White exhibited some aberrational forms of the two " Fritil-
lary " butterflies Melitaea artemis and Argynnis euphrosyne. One speci-
men of the former species had the ochreous " ground colour " of the
upper side abnormally pronounced, developing into large tesselated
spots, while another specimen showed a subdued orange-brown tone per-
vading more or less the whole field of all the wings. The variation in
A. euphrosyne consisted in the enlargement of the black patches, more
especially on the lower wings, and the commingling of them near the
basal portion into one black area containing a conspicuous eye-like spot
of black upon a well-defined "mirror" of the orange-brown colour of
the groundwork. The normal forms of each species were placed with the
specimens for comparison. Mr. White also exhibited an interesting
* It may be worth recording that in the above-mentioned year—which will long he
remembered by entomologists as the great "Colias year"—Colias edusa was extremely
common in many parts of the Epping Forest district. In Br. Sewell's clover fields at
Woodford Bridge we secured a very long series of C. edusa ab. helice, including one or
two intermediate forms such as those alluded to by Mr. Meldola.—Ed.