THE AUSTRALIAN NATURALIST. ‘ 73 
numerous specimens formerly good have perished through 
weathering. Excellent stems of calamites, mostly Phlyllotheca, 
whose living representatives are seen in the horsetail (Hquise- 
tum), have been found here, and as they may measure as much 
as 4 or 5 inches across, the plants themselves must have been 
of considerable size. The modern equisetum, the sole living 
genus, 1s quite a moderate sized plant. 
In the fossils the ribbed structure of the stem is well 
marked, and the division into nodes and internodes may be 
clearly seen. The whorl of leaves which occurs at the nodes and 
which is comparatively small, when found in the fossil state is 
known as Annularia. 
Perhaps the next commonest fossil of the Narrabeen beds 
is Thinnfeldia, in appearance closely resembling a modern fern. 
This had feathery pinnules, and was of considerable size. The 
specimen exhibited shows the branching and general mode of 
growth very well. It was identified by Miss Brewster as 7’. 
odontopteroides. Other plant remains occur including the ferns 
Taeniopteris and Macrotaeniopteris. 
THE COCOON OF THE CUP MOTH. 
By C. A. S'TEINBECK. 
In order to ascertain how the larva of the Cup Moth ob- 
tains a “lid” to its cocoon, I have watched the spinning of three 
cocoons with the following result: The larva commences by 
spinning web enough to cover half its length; it then doubles 
itself completely backwards, and in this manner draws the re- 
mainder of its body into the web. In this position (head and 
tail segments touching) the larva completes the whole spinning 
process; the cocoon constantly varying in shape with the many 
turnings of the doubled-up caterpillar, as it spins rapidly and 
continuously for four and a half hours. When the spinning 
ends, the head and tail segments are always at the base, and 
this gives the cocoon its well-known shape. The larva now 
ejects a considerable amount of milky-white fluid on one side of 
base, and this is spread up the corresponding side of the cocoon 
by violent contractions and extensions of the body. A second 
quantity of the fluid is then ejected at the opposite side of the 
base, and is worked up the other half of cocoon in similar 
manner. Owing to the forcing of the body against the apex 
(after each contraction) very little, if any, of the fluid can enter 
