352 THE ENTOMOLOGIST. 
particularly those of genus Potomogeton, and the young, on 
escaping, swim freely in the water, probably feeding on 
minute animalcules. Be this as it may, it has been ascer- 
tained by some of the most indefatigable observers, that they 
do not acquire sucking-disks and their parasitic economy 
until after the sixth moult. 
Beetle destroying Ten-weeks’ Stock.—Can you suggest a 
remedy under the following circumstances :—My ten-weeks’ 
stock came up regularly and grew very well until three 
weeks back, when it was coming into blossom; it was then 
suddenly attacked by myriads of a little jumping beetle, 
some of which I have secured and send for you to examine. 
All chance of blossom seems gone; the leaves, as well as the 
flowers, being eaten by this miserable little wretch, which is 
no bigger than a flea. JI have killed thousands, by shaking 
the stock over a shallow basin of hot water, in which they die 
instantly and float on the surface; but more remain behind, 
and the cry is still “they come.”—#. EF. N. 
The beetles were immediately dispatched to Dr. Power, 
who thus courteously replies to my request for a name :-— 
“The Haltica is Phyllotreta peecilocerus, of Waterhouse’s 
Catalogue; obscurella, J/l., of Crotch: it is very common 
everywhere.—J. A. Power.” The ten-weeks’ stock (Cheiran- 
thus annuus) is a native of the South of Europe, and was 
introduced as a garden annual one hundred and forty years 
ago. There is no plant more familiar, and none more 
universally cultivated. In the South of England it is difficult 
to find a cottage-garden which is not decorated with the 
bright flowers of this favourite. The Phyllotreta is a native of 
this country, like the turnip Haltica, or “ turnip-fly,” as it is 
very erroneously called; but it would remain unnoticed, did 
we not provide it with a more agreeable esculent than it finds 
in the hedge-rows. 
Entomologists in France.—On the wrapper of the July 
‘Entomologist’ I gave the following scraps of news received 
from France, too late for insertion in due order; they are all 
extracted from the ‘Petites Nouvelles Entomologiques :’— 
“The second siege, by which Paris has suffered so much, has 
spared the persons of entomologists, but has utterly annihi- 
lated, or greatly damaged, many of their collections and 
libraries. Dr. Laboulbéne, who resided in the rue du Bac, 
