ii6 
Swift Moths. 
[may, 
of ornamental pattern are sometimes used, but the question 
of expense usually prohibits their use for cottages. A tiled 
roof should have a pitch of not less than 40 0 . Ordinary 
slates are a cheaper form of roof covering than tiles, but 
should not be laid to a less pitch than 30 0 . 
There are also several artificial substitutes on the market 
in place of tiles and slates. The asbestos-cement slates seem 
to be rapidly rising in favour in some parts of the country, 
but it has yet to be proved that they are as durable as good 
Welsh slate. The advantages claimed for them are that 
they are light, weather-proof, non-conducting, and economi- 
cal, the cost being stated to be less than one-half that of 
Broseley tiling. The rafters are usually spaced 2 ft. apart, 
thus effecting a saving in the timber as compared with the 
spacing for ordinary slates. 
This article has been devoted to the general treat- 
ment of the subject, and has aimed at setting forth the main 
principles on which unpretentious but useful cottages can be 
provided for labourers at a reasonable cost, without sacri- 
ficing comfort or durability. The accompanying designs will 
serve to illustrate how such cottages can be erected, at the 
prices stated, to meet the present-day needs of agricultural 
labourers. 
SWIFT MOTHS (Hepialidae). 
R. Stewart MacDougall, M.A., D.Sc. 
The Hepialidae are an isolated family of moths showing 
some primitive characters. There are five British species. 
Three of these feed — in the caterpillar stage — on and in the 
roots and rhizomes of the bracken fern (Pteris aquilina). The 
two troublesome species are the Small Garden Swift Moth 
(Hepialus lupulinus, L.) and the Ghost Swift (Hepialus 
hamuli, L.). The caterpillars feed underground. 
Hepialus lupulinus. — The caterpillars of this moth are very 
destructive; their food plants belong to many Natural Orders. 
In the past three years the caterpillars have been reported to 
the Board as damaging — often severely — the underground 
parts of daffodils (the bulbs especially), peonies, dahlias, 
