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' ‘THE AUSTRALIAN NATURALIST. 
BOOK-LICE ON CITRUS ‘TREES. 
-By Kerra McKrown. 
During the Spring months a dark-winged book-louse is of 
common occurrence on the citrus trees on the Murrumbidgee 
irrigation areas. I have as yet been unable to ascertain the 
specific name of this curious little insect, but as very little ap- 
pears to have been published with regard to its habits, or of 
Psocidae generally, these notes may prove of interest. Mr. 
Froggatt in his “Australian Insects” simply refers to a book- 
louse depositing its eggs on orange trees, but does not identify 
the species or give any further particulars. 
The eggs are deposited in large numbers on the leaves, and 
fruit of citrus trees, and occur in small clusters, each ranging 
from about six to fifteen olive green or copper coloured eggs, 
which are large in comparison with the size of the parent. Hach 
group of eggs is covered with a tightly stretched silken sheet 
of a glassy appearance; through which the enclosed eggs may be 
clearly seen. Although insects in captivity oviposited freely 
under observation, I did not observe the spinning of the silken 
covering sheet, as in confinement the book-lice generally left the 
eggs open, and made no attempt to cover them in any way— 
under natural conditions, however, it is exceptional to find the 
‘eggs without a more or less complete cover. 
The eggs hatch normally in about three to four days. The 
small larvae are almost colourless, and bear a strong resem-: 
blance to minute, newly hatched cockroach larvae, or to a small 
compressed termite. {lhe antennae are threadlike, and the ocelli 
which are conspicuous in the adult insect are curiously lacking 
in the larvae stages. The larvae increase rapidly in size and 
soon show the well developed wing pads of the nymph, but in 
other respects changing little in appearance from the larvae 
stage. 
The adult insect possesses well developed wings of a dark 
smoky colour, and flies with a rather fluttering action, but. are 
normally reluctant to take flight. During the heat of the day 
they may be seen actively running about over the foliage of the 
trees. There appear to be several broods in a season, and at 
any one time specimens may be obtained in all stages from the 
egg to the adult insect. The insects feed in all stages upon the ° 
black smut or Fumagine which is usually present on trees in- 
fested with the common Brown Olive Seale (Licanium olae) de- 
veloping profusely on the sticky honey-dew exuded by the scale 
insect. Under a lense the book-lice may be observed feeding 
