140 THE ENTOMOLOGIST’S RECORD. 
Collective inquiry as to Progressive Melanism in Moths.—Memo- 
randum from the Evolution Committee of the Royal Society. 
The committee appointed by the council of the Royal Society to 
promote investigation of facts relating to ‘‘ variation,” ‘‘ heredity,” 
‘‘ selection,” and other phenomena connected with evolution are 
desirous of instituting a collective investigation into the progressive 
melanism of certain moths, particularly Geometridae. It is well known 
that in certain districts, especially within the British area, dark forms 
of several species of moths have recently appeared and become increas- 
ingly abundant. ‘There is reason to believe that these dark forms are 
in some cases extending into other districts and even to the Huropean 
continent. It is to be regretted that no systematic or statistical records 
of these phenomena have been kept, and it appears to the committee 
that if such a record be now instituted and continued for a period of 
years it cannot fail to have considerable scientific importance. The 
matter is one that may conveniently be made the subject of collective 
investigation, and the committee will be glad to hear from any ento- 
mologist who may be willing to contribute now, or hereafter, particulars 
as to the condition of these species in the district or districts with 
which he is personally familiar. The returns should relate as far as 
possible to specimens found in a wild state, whether as imagines, or 
pupe, larve, or eggs. Information respecting specimens bred from 
wild parents must be kept distinct. It is thought desirable that the 
enquiry should for the present be confined to the following species: 
Acidalia aversata, Amphidasys betularia, Boarnia repandata, 
Camptogramma bilineata, Gnophos obscurata, Hemerophila abruptaria, 
Hybernia progemmaria, Phigalia pilosaria, Acronycta psi, Ayrotis corticea, 
Aplecta nebulosa, Polia chi, Venusia cambrica, Xylophasia polyodon. 
The schedule in which it is suggested that the returns should be 
made is termed Schedule A. It is desired that the return for each 
species be made on a separate schedule, and the secretary will be glad 
to furnish a supply of these schedules to any one who may be willing 
to assist. Since confirmatory evidence is of especial value, the 
committee are desirous of receiving returns made independently by 
different persons for the same district. It is of course hoped that 
returns may be obtained for districts in which the dark forms are 
still unknown. ‘The secretary will be glad to examine and prepare 
descriptions of any illustrative specimens lent to him for that purpose, 
and in suitable cases arrangements will be made for photographing 
such specimens. 
Historica Evience.—As the changes in question have largely 
taken place within living memory, it is hoped that those who have 
personal knowledge of the facts may be induced to put them on record 
in such detail as is still possible. Much information of a historical 
character is of course already printed in the scientific journals, but a. 
more detailed account of the facts would be of great value. With this. 
object a special schedule (B) marked ‘“ Historical’? will be issued to 
those who will fill it up. 
On publication full acknowledgement will be made of all help 
received. All communications should be addressed to the Secretary of 
the Evolution Committee, W. Bateson, Esq., F.R.S., Merton House, 
Grantchester, Cambridge.—May, 1900. 
Errata.—p. 109, line 1, for “first” read “ post’; line 2, for ‘‘free ’’ reac 
‘ pre’ (-spiracular). 
