NATURAL HISTORY QUERIES 175 
question. Till then, and probably for ever after, I shall look upon the cuckoo- 
spit insect as innocent. 
July , 1904. Edmund Tiios. Daubknv. 
151. Honey-dew. — During the long spell of hot, dry weather, which we 
have been enjoying of late, we have had here in Richmond a most unusual pro- 
duction of honey-dew. Hawthorn leaves have been glazed on the upper surface, 
and have even dripped to the ground ; while the Black Italian I’oplar {Populus 
monilifera) stieamed almost to the same extent as did the Linden, so that the 
pavement beneath them actually ran with the saccharine exudation. I noticed 
that it proceeded mostly from the upper surface of the leaves, mostly on parts 
exposed to direct sunlight, and most abundantly on the hottest days. For the 
first week or two the leaves looked healthy, and there was no sign of aphides on 
them ; but latterly numbers of white woolly forms made their appearance on the 
Linden leaves. In his article on the Pathology of Plants in the Encyclop;vdia 
Britannica, Professor Marshall Ward says : “ In many cases the punctures of 
Aphides and Coccide;e are shown to be responsible for such exudations, and at 
least one instance is known where a Fungus — Claviceps — causes it. But it also 
appears that honey-dew may be excreted by ordinary processes of over-turgescence 
pressing the liquid through water-pores.” G. S. Bouliikr. 
NATURAL HISTORY QUERIES. 
27. Dytiscus marginalis. — In the early part of last June I placed three 
females of this species in a small aquarium with one male, and plentifully sup- 
plied them with food. Next morning I found two of the females dead. The 
remaining two are still (July 5) very much alive. Many Selbornians doubtless 
keep aquaria and have had many specimens of this species under observation. 
I should like to ask them through the medium of Nature Notes whether they 
have observed female Dytisci kill one another, especially when the food supply 
(such as small Crustacea) was in abundance. If mine did so, which is quite 
probable, as they were perfectly healthy the previous day, then subsequent obser- 
vation suggests that the battle might have been fought for the sole possession of 
the male. This is, however, a point which certainly would require further and 
very careful observation. 
\z%, Mansfield Road, N. IV. J. W. Willia.ms, 
M.R.C.S., F.L.S. 
28. Sundew. — Some weeks since I found some Sundews growing, and 
brought home two plants. When I found them the hairs, or tentacles, were a 
bright red, but since I have had them, although they seem perfectly healthy, the 
hairs are quite green. I give them flies, but kill them first, would that affect the 
colour, do you think? Since I have had them they have grown much larger, 
and have developed peduncles, bearing flowers, but they seem some time in 
opening. Will you kindly explain the reason in Nature Notes ? 
M. II. Crafer. 
[The reddening of the Sundew is largely produced by direct sunlight or 
consequent drought ; greenness, by vigorous growth in comparative shade. It 
is not probable that the plant can discriminate dead flies from live ones. Its 
flowers are almost always cleistogene, i.e., fertilise themselves without opening. 
In forty years’ observation we have only once or twice seen them open. — E d.A^.A’'.] 
SELBORNE SOCIETY NOTICES. 
Council Meetings. — There will be no meeting of the Council during 
August. The Publications Committee will meet on Monday, August 8, at 
5.30 p.m. 
New Members. — Miss A. Adams, Shepherd’s Bush ; Miss Gibbs, Upper 
Norwood; Miss A. Brazil, Llanbedr ; North Middlesex Junior Branch, Master 
Claude Pidcock, Hampstead ; Miss Sophie Farmer, Hampstead ; H. J. Allen^ 
Esq., Kentish Town. 
