9 
so greatly developed, and that there it occurred in a great number of 
families and sub-families, including the whole of the families com¬ 
prised by the butterflies’. The paper was divided into two parts 
under the headings : (1) Why has transparency arisen ? (2) How 
has transparency arisen ? Under the first the author gave his reasons 
as the following : (a) For increased warning aspect, (/;) for the reverse 
or eflacive colouration, (r) for possibly increased speed on the wing. 
Following in the wake of all these primary developments, mimicry 
produced many similar forms. Under the question, “ How has 
transparency arisen?” the remainder of the paper was devoted. A 
short recapitulation of Professor E. B. Pouiton’s paper in the Trans. 
Linn. Soc., 1898, pp. 558-612, was given, followed by the author’s 
own research in other species and groups. Details were given at 
o s det able length concerning two British Guiana groups, (1) one 
composed of the species Ayyrta micilia and Euayra cnelestina, of the 
Syntomidae ; Ksthenntpsis sericma, an Erycinid; Pseudarbessa decorata, 
a Geoiuetrid, and Iostola divisa a Hypsid; (2) a group composed of 
Leucothyris zar&pha , Napeoymes, n.sp., 1 thornia florula, and Heternsais 
nylphis, all of the Ithomiinae, Laurnn partita, a H\ psid moth ; Hyrmina, 
n.sp., a Geometrid moth. Stalarhtis erelina, and Stalarhtis phaediisa, 
Erycinid butterflies. In every case it was found that the greatest 
development towards transparency was the discal area of the hindwing. 
The discal area of the forewing followed next, and the apical area showed 
least and latest development of all. At the close of the paper Mr. A. 
W. Mera said it was noteworthy that nearly all, if not quite all, the 
transparent species were diurnal in habits. He thought that the 
British Sesiides and Hlgeriids were extremely difficult to detect on the 
wing. Mr. L. B. Prout proposed a hearty vote of thanks to Mr. Kaye. 
He asked, were not hair like scales ancestral and not a late development, 
and Mr. A. Bacot seconded the vote, he thought with the author that 
there must be several different reasons for transparency. He suggested 
that the smooth membrane of the wing tended greatly to reflect the 
glare from the sun and unless the pursuing bird was at the right angle 
the object would not be seen. In some specimens even the body was 
so clothed that it might also reflect the light as well as the wings. 
Mr. Allred Sich supported the vote of thanks, and said that in the lower 
lepidoptera the hair-like scales were an ancestral character, the scales 
being developed later. Dr. T. A. Chapman said, as an extension of Mr. 
Bacot’s idea, he thought the retention of transparent scales was 
probably for this purpose of light reflection. He agreed with Mr. Kaye 
that in a great number of instances the hair was a later development 
than the more usual flat scale. It could, however, always be ascertained 
by the scale sockets, the ancestral hair being set on a round spot only 
while the highly evolved hair-like scale was set in a cup shaped socket. 
The vote of thanks was put and carried, and Mr. Kaye replied. 
March 15th, 1904.— Bleached Synopsta abruptaria. —Mr. Shepherd, 
a specimen of Synopsia abruptaria, bleached on both bindwings, which was 
caught flying, also the form consnbrinaria of Boarmia consort aria. 
Burrows of HUgeria formic.eformis.— Mr. W. -T. Kaye, a stump 
of osier with burrowings of Aeyeria formicaeformis. 
Bred Lycia hjrtaria. — Mr. C. P. Pickett, Lycia hirtaria, bred after 
having been two years in pupa. 
