130 THE MOTHS OF THE BRITISH ISLES. 



July. Alder, sallow, and lime have also been mentioned as 

 food plants. 



The rough, blackish, or sooty-brown chrysalis is enclosed in 

 a coarse netted cocoon, dark brown in colour, and more or less 

 covered with moss, leaves, or other material, among which it is 

 spun up, generally on the ground, but sometimes just under the 

 surface. Assisted by the points on the rings of the body, the 

 chrysalis is able to work itself partly out of the cocoon, and this 

 it does some days before the moth emerges. 



The moths usually emerge in late March and in April, 

 earlier or later in some seasons. They do not always come 

 up the year after pupation, but often remain two or more 

 winters in the chrysalis. 



The males fly in the sunshine, and are very strong on the 

 wing ; the females are not active until dark. This sex has 

 been found resting on the twigs of birch, also on heather, 

 and occasionally on a tree trunk. The males "assemble" 

 freely to a freshly emerged female. The species inhabits 

 the more open parts of woods and forests, moors and hillsides 

 where birches flourish. It is probably more plentiful in its 

 Scottish localities, such as Rannoch and Forres, than else- 

 where, but it occurs also in Aberdeenshire, Kincardineshire, 

 and Argyllshire. In England it seems to be not uncommon 

 in Wyre Forest, Worcestershire, and the Reading district in 

 Berkshire. It used to be so plentiful in Tilgate Forest, Sussex, 

 that over a hundred males were brought to the net in one day 

 by a bred female put down to allure them. This happened 

 some fifty years ago, and compares curiously with a record of 

 one male attracted by a female in Tilgate Forest, April 13, 

 1869. Other localities in Sussex that have been mentioned 

 are St. Leonard's Forest and near Petersfield ; it has also 

 been found in Herefordshire and in some parts of Suffolk. 

 Distributed over Central and Northern Europe, the range 

 extending to North Italy. 



