96 
The Queensland Naturaijst. Vol. I. 
desired, and then remain at rest upon the protective portion. 
I have noticed, too, that they have a singular habit of 
sliglitly trembling when frightened, and whilst trusting in 
their colouring, nestle as closely to the bark as possible. 
The adult forms are rarely, if ever, black, but streaked 
with various sliades of yellow, brown, and grey, and are 
often found hopping heavily on roads and bush tracks, etc. 
They are said to rest for protection on bark at the bases 
of large standing trees, where, assuming a vertical position, 
they harmonise in form and colour with the projecting 
irregularities so characteristic of the bark surface of 
Eucalyptus ohliqua. and other gums. 
Another insect with a partiality for similar resting 
plaices is Hydriomena anthracinata, one of the Victorian 
‘‘ geometer ” moths, found plentifully in certain localities 
during summer on charred trees, and in burnt-out shells 
of logs and stumps. “ The fore-Avings on the upper surface 
are entirely covered Avith various shades of black and grey, 
fonning a complete disguise to the insect Avhen at rest.’’ 
Op. cit. 
This s])ocies is especially interesting from the fact 
that, although possessing exceptionally good protective 
colouration, it has not yet learned to place implicit reliance 
on it : since, though trusting it, in so far. perhaps, as insect 
eating birds are concerned, it flies hastily aAvay on the 
a])proach of larger bodies. Whilst escaping, its quick, 
erratic, and often prolonged flight suggests the utmost alarm, 
and. as it is hard to folloAv and extremely difficult to catch, 
1 am inclined to believe that all such times it may feel safer 
on the wing than vvhen settled, and use its protective 
colouring as a last resource. I have freqxiently collected 
this species, and had abundant opportunity of watching 
its habits. l)ut cannot recollect a single occasion on Avhich 
it has allowed me to approach nearer than two or three 
feet before deserting its resting place. 
THK QUEENSLAND SPIROGYRA. 
By the late F. Pigram (State School, Freestone, WarAvick). 
The genus Spirogyra is easily recognised. To the 
naked eye the plants usually present the appearance of 
bright-green, cloud-like, floating masses, suspended in 
stagnant Avater, and are generally exceedingly slimy to the 
touch. Looked at more closely, they are found to consist 
of great numbers of threads, of varying thickness and 
length, in different species, often matted and mtertAvined, 
but in reality quite inde])endent of one another, for every 
thread is a distinct plant. When the masses have the 
ap])earance above described, the plants are in the sterile, 
