1 88 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
It is clearly demonstrated that, with the single exception of colour, the turning 
of orchards down to grass is a failure. 
The foliage, growtli of trees, and weight of crop under grass were very much 
inferior to the check orchards in tillage. In fact, in all sections the grass orchards 
steadily deteriorated almost to the total destruction of the trees, while the 
tilled sections as steadily improved. 
In the case of a tilled orchard set down to grass, the evil effects of grassing 
plainly showed themselves in the first season. — C. P. C. 
Apples, Cost of Producing, in Maine, U.S.A. By A. K. Gardner (U.S.A. Dep. 
Agr., Bull. 3, 22 pp.). — A careful examination of the cost of producing Apples 
in nine orchards on a uniform system. It is concluded that the cost of a barrel 
is i dollar when the crop equals two barrels a tree, and i£ dollar when the 
production is one barrel. — E. A. Bd. 
Aquatic Compositae. By J. Hutchinson (Gard. Chron. June io, 1916, p. 355 ; 
with 4 figs.). — Points out that, as aquatic plants of the present day are most prob- 
ably derived from terrestrial seed-bearing plants, they should represent forms that 
have been surpassed in the struggle for existence by better equipped rivals, and 
have escaped destruction by taking to the water. Therefore the more primitive 
groups of a family should supply the aquatic members. Thus in the Compositae 
they should show these characters : (1) foliaceous involucral bracts ; (2) scaly 
elongated receptacles ; (3) foliaceous calyx (pappus) ; (4) free anthers. 
The curious aquatic Compositae, Bidens Beckii, Cotula myriophylloides, Pedis 
aquatica, and Erigeron heteromorphus, are described and figured. — E. A. B. 
Arsenate of Lead, The Toxic Values of. By H. V. Tartar and H. F. 
Wilson (Jour. Econ. Entom. viii. Oct. 1915, pp. 481-486). — Two different arsenates 
of lead are present in the commercial material — lead hydrogen arsenate (acid) 
and basic lead arsenate (neutral). Careful experiments conducted with both 
substances in a pure state show the first is quicker-acting and more efficient 
in strengths containing equal quantities of arsenic than the second. Lead 
hydrogen arsenate contains approximately 33 per cent, arsenic oxide (AsO,), and 
basic lead arsenic 25 per cent. — G. W. G. 
Bags, To keep Mice from Eating (Queensland Agr. Jour. June 1915, p. 272). — 
Many farmers experience great difficulty in keeping their wheat bags free from, 
the depredations of mice and rats. A New South Wales farmer states that 
if each of the bags is rubbed over with a few handfuls of sulphur, mice will 
never touch them, and the same procedure would probably answer in the case of 
rats. Bags thus treated have stood from stripping to sowing time without a 
hole having been made in one of them. — C. H. H. 
Beneficial Insects in Hawaiian Islands, Some Results of the Intro- 
duction of. By Otto H. Swezer (Jour. Econ. Entom. viii. Oct. 1915, pp. 450- 
457). — Attention is drawn to the fact that very few of the native insects of these 
islands have become injurious to cultivated plants, and that insect pests there 
are in most cases foreign insects which have arrived through the channels of 
commerce. In 1890 the Australian lady-beetle (Novius cardinalis) was intro- 
duced to control the cottony cushion scale with great success, the scale no 
longer being a menace. About a dozen species of lady-birds were successfully 
introduced by 1896, mostly from Australia and the Orient. Among these were 
Cryptolaemus montrouzieri, Rhizobius ventralis, and R. toowoombae, feeding on 
various mealy bugs ; Coelophora inequalis, Platyornus lividigaster, Scymnus 
loewii, and S. notescens, feeding on plant lice ; Orcus chalybaeus, and Chilocorus 
circumdatus , feeding on scale insects. 
Among the most valuable of the introduced coccid parasites are Encyrtus 
fuscus, Blepyrus marsdeni, Microterys flavus, Apentelicus kotinskyi, Adelencyrtus 
odonaspidis, Scutelliota cyanea, Tomocera calif ornica, T. ceroplastis, Aneristus 
ceroplastae, Coccophagus orientalis, C. lecanii, Aphelinus diaspidis, and Aspidio- 
phagus citrinus. In 1895 Mr. Koebele (Hawaii) introduced from Japan Chalcis 
obscurata and Macrodyctium omiodivorum, which are doing much good in killing 
off the leaf -rollers on sugar-cane and coconut palms. Another phase was the 
introduction in 191 2 of insects to control the spread of Lantana. A study of the 
insects preying exclusively on this plant in Mexico was made, and the most 
effective checks introduced are the little black seed-fly (Agromyza sp.) and two 
moths (Platyptilia pusillidactyla and Crocidosema lantana), which feed in the 
flower clusters. The results were good, but the introduction of insects to feed on 
weeds seems to be a dangerous experiment. A most notable introduction was 
