192 THE AUSTRALIAN NATURALIST. 
time, the caterpillar settled down in a corner and commenced. 
to chew the wood of the case. This it made into a soft pulp, 
and used, for the cocoon. It was slow work, so we scraped 
some of the wood with a knife, and offered it as compensation. 
for our neglect. The caterpillar eyed it suspiciously, turned 
it over once or twice, and then went on with its work—con- 
tempt expressed in every hair. 
The next morning the cocoon was only half finished. _To- 
wards the end things became quite exciting, and the school 
children were so interested that they stayed an hour over 
time to see the finish. The opening of the cocoon was left at 
the top end, and the caterpillar, working feverishly as if 
afraid that fate would overtake it too soon, did not seem to 
be able to fill up the gap, with itself inside. A good deal of 
time was spent in experimenting, trying to bring the pulped 
wood from outside. Finally the task was finished by chew- 
ing more wood from inside the cocoon, and sealing up the 
hole from the inside. 
Antheraea eucaly ptt. 
We had some Emperor Gum moth’s eggs in the same case. 
Although quite a number hatched, they appeared to be deli- 
cate, and we only reared one caterpillar. _ When about three- 
inches long it changed colour, and began to spin its cocoon. 
We put some silk from a silk-worm’s cocoon beside it, and 
though it appeared to resent our interference and showed 
fight at first, it used our silk. 
The cocoon is old now and stained, and the silk does not 
show very much; but when it was new the yellow floss couid 
be seen quite plainly, woven through and through the little 
structure. 
NOTES ON SOME FORMS OF ASSOCIATION 
AMONGST PLANTS, PARTICULARLY IN _ RE- 
GARD TO BACTERIAL NODULES AND MYCOR- 
HIZAE IN AUSTRALIAN PLANTS. 
(By W. M. Carne.) 
Root Nodules in Legumes. — During the latter part of the 
19th Century an explanation was found for what Agriculture 
had long recognised as a fact, namely, that the growth 
of a leguminous crop results in an increased growth of a suc- 
ceeding crop, such as cereals or roots. Hellreigel and Wil- 
farth then demonstrated the power of legumes to assimilate 
free nitrogen from the air in the soil by the aid of certain bac- 
teria. These organisms, named Pseudomonas radicicola, live 
symbiotically in the roots of leguminous plants, forming small 
