Marvels of the Universe 1103 
of which bores her way into the nest and lays her eggs there. The young grubs feed on the nest 
materials, etc., and when full-fed, make a hard cocoon of earth and vegetable refuse in which to 
pupate. When the perfect beetle emerges, it flies away. 
Another beetle, Clythra, which is red spotted with black, somewhat like a “ lady-bird ” in appear- 
ance, has a most interesting life-history, which has been elucidated by the writer. The beetle itself 
feeds on the young leaves and shoots of birch-trees, etc. Its female seeks a tree or shrub, above 
or near a nest of the Wood Ant, and drops her eggs on the ground. She covers the eggs, which 
she holds with her back feet, with excrementitious matter, which she arranges in layers. This makes 
them resemble a small bract, or part of a plant ; in fact, they look exactly like the end of a birch 
catkin. The ants pick this up and carry it into the nest, as they do with bits of vegetable refuse. 
When the young grub hatches, it builds a small black case on the covering of the egg. This case 
has V-shaped ridges on one side, and is constructed of earth mixed with excrementitious matter. 
As the grub grows it enlarges its case, by scraping off portions of the inside with its jaws, and 
plastering more on the outside. It feeds on the vegetable refuse of the nest, and also on the pellets 
of the ants. When full-grown, the grub fastens the mouth of the case to a bit of wood, or other object 
in the nest, and turning round inside the case, changes to a chrysalis. When hatched, the perfect 
beetle cuts a rim round the end of the case with its jaws, forming a cap which it forces off. It then 
crawls out of the nest and flies away. 
A SEAWEED THAT MAKES LIMESTONE 
BY F. CHAPMAN, A.L.S., F.R.M.S. 
THERE are some seaweeds, like the jointed Halimeda and the nullipores of the coral reefs, as well 
as the corallines of the British shores and the Mediterranean, which have the remarkable faculty 
of encrusting their fronds with carbonate of lime. 
Halimeda is a green seaweed, which flourishes luxuriantly on the outer reef slopes of coral islands, 
and also in the lagoon. At 
Funafuti, in the South Pacific, 
it was found from a foot or 
so below sea-level to forty-five 
fathoms. It forms great tufty 
masses, and where the con- 
ditions are favourable, the 
separate triangular joints of 
the seaweed accumulate to 
form a thick bed of lime- 
stone. 
Limestone rocks due _ to 
the agency of this little plant 
have been found in the Solo- 
mon Islands, Christmas  Is- 
land, at Funafuti, and in 
the New Hebrides. (Collected 
by Dr. Douglas Mawson, 
of the present Antarctic Pit bul 
Expedition.) In the deep THE WOOD ANT. 
ening at TFonetintl de Gio 9, AROSE am Oh re ee ene ee 
tached joints of this seaweed other birds. 
(H. Bastin. 
