18 : THE AUSTRALIAN NATURALIST, 
A. Milligan, a note on ‘‘Development of the Emperor Gum 
-Moth.’’ Mr. A. A. Hamilton contributed notes on the 
**Adventituous Aerial Roots of Cycadaceae.’’ 
It was unanimously decided to hold a ‘‘ Working Bee”’ 
on Friday evening, 12th April, to arrange and catalogne 
the valuable collection of books in the Society’s Library. 
gor : 4 
NOTES ON MICRODON, A SYRPHID FLY. 
(By L. Gallard.) 
The specimens of Microdon larve, exhibited at the 
meeting in March, 1917, were found in February in the 
nest of a small black ant in the decayed bark of an iron- 
bark tree at Epping. The mature larva is crescent shaped, 
about five-sixteenths of an inch in length and three-six- 
teenths wide. The ventral surface is flat, and the organ- 
ism resembles a flattened Dacylopid scale more than the 
larva of a fly. The body is white, and is covered with a 
fine network pattern; the margin is fluted like the edge of 
a coin. On the dorsal surface near the posterior end is 
a hard, horny stigma or spiracle, about one-sixteenth of 
an inch in length. As the larva develops, two horny pro- 
cesses grow up through skin at the anterior end, like a. 
pair of horns. These I take to be the sheaths of the long 
elbowed antennx of the adult fly, and it also appears to 
be by these that the pupal skin is broken at the time of 
emergence. When the larva is at rest the head is drawn 
in so as not to be visible, but when in motion, the tiny 
head can be seen protruding from under the front margin. 
The head, in a preserved specimen, is seen to be telescopic, 
and eapable of being drawn back into the body at about 
where the third segment would be. It appears to have 
the ordinary mouth organs of a fly larva, terminating in 
a pair of hardened styles. When ready to pupate, the 
larva turns brown and the outer skin hardens, but the 
shape does not alter. 
The adult is a longish fly, somewhat resembling a 
wasp in shape. The colour is dark brown, with old gold 
markings. The abdomen consists of three visible | seg- 
ments marked off by two bands of golden pubescence, and. 
is attached to the thorax by a long flat pedicle. It has a 
long telescopic ovipositor, 
