286 I.EPIDOPTERA. 



fSeptember till April or May; on duckweed (Lem7ia), frog- 

 bit {^Hydrocharis morsus-ronce)^ and other water-plants. 

 Living entirely in the water, cither at the surface or deeper, 

 in a case formed of leaves of duckweed, or pieces bitten from 

 the leaves of some other water plant ; readily protruding its 

 anterior half in order to feed or examine its surroundings; 

 and when thus visible appearing as though silvered over 

 from a film of air which covers it. The case is oval, half an 

 inch long, and not readily noticeable among the floating weed. 



Pupa a little more than three-eighths of an inch long ; the 

 wing, antennae, and leg-cases well developed, the latter pro- 

 jecting a little, free from the body, which is smooth and 

 shining, head and thorax rounded off ; anal tip rather blunt, 

 and having on each side a rather angular projection ; spiracles 

 flat, circular, button-like ; colour worn shining brown. In 

 an oval cocoon, thickly and smoothly lined with white silk. 

 (W. Buckler.) In the larval habitation, or among fresh bits 

 of leaf in the water ; often upon the surface, where a few 

 leaves of the Lemna drawn together form little raised 

 nodules. 



The moth hides during the day among vegetation on the 

 borders of ponds, lakes, rivers, and especially wherever the 

 water is sufiiciently still for the growth of duckweed. Here 

 it is readily disturbed by day, and flutters lazily away to a 

 similar hiding-place, the female being less willing to fly at this 

 time than the male. At about sunset and onward till dusk 

 every male is buzzing gently about over the water, and in the 

 most favoured spots, such as the broad ditches which drain the 

 fens of Norfolk, quite an extraordinary sight is presented by 

 the snow-white males flying in thousands over the water, all 

 at the same elevation over the surface, and all buzzing in 

 the same gentle manner. Later at night the females fly 

 higher and more over the country, coming willingly to a 

 strong light. Common throughout England and Wales, to 

 Yorkshire and Durham at least, and also all over Ireland ; 



