46 Transactions. — Zoology. 



found that two of the larva3 had changed into pupae resem- 

 bhug the one I found two years before. These unfortunately 

 became mouldy and died, and it was not untd the following 

 April that I succeeded in rearing the true fly, which I dis- 

 covered on the morning of the 4th standing beside its old 

 pupa-skin. Two enlarged drawings were then made, and for- 

 warded to Mr. SkiTse, of Sydney, and Baron Osteu-Sacken, of 

 Heidelberg, Germany. Both these gentlemen had been pre- 

 viously furnished with specimens of the larvae in alcohol. 

 They then expressed their opinion that the fly of which I sent 

 a di'awing probably did not result from the luminous larva, 

 and that it would be desirable to postpone publication until 

 another specimen had been reared. Convinced though I was 

 of the accuracy of the observation of the 4th April, I deter- 

 mined to verify it, and again prociu'ed larva?, which all died. 

 On the 10th July, 1890, I got about twenty large larvae, 

 spending upwards of three hours in the bed of the stream. 

 Two of these changed during August into pupae, one of which 

 died, but the other gave rise to another fly exactly resembling 

 the one reared on the 4th April, 1889. The circtimstances 

 connected with the emergence of this fly are so entirely con- 

 clusive that it may perhaps be well to relate them in detail. 

 On examining the ptipa at 8 a.m. on the 14th, I observed that 

 it had become much paler in colour. At 2 p.m. I noticed the 

 fly perched on it, with its head down towards the tail of the 

 pupa, and the extremity of the abdomen of the fJy still tcithin 

 the pupa-skin. In tliis position it remained luitil the follow- 

 ing day at 5 p.m., when I transferred the fly into a large 

 glass-topped pill-box, which I placed on the table in my 

 sitting-room. On returning to the room at 7 p.m. without a 

 lamp, I v,-as astonished to see the inside of the box brilliantly 

 lit up, the extremity of the fly's abdomen giving oitt a strong 

 hght about half as bright as tliat emitted by a full-grown 

 larva. The whole of the phenomena relating to the emer- 

 gence of this fly from the pupa, and its subsequent luminosity, 

 were also observed by my brother, who was present at the 

 time, and can fully corroborate these statements if necessary. 

 As this was a female fly, I decided to take her up into the big 

 gully in the Gardens, where the larvae are abundant, and see 

 if she would attract males. As soon as I arrived I put the 

 box down in the bed of the stream, and the fly immediately 

 lit up so as to again strongly illuminate the inside of the box. 

 There were lots of larva? all round, so that I considered it 

 likely there were also flies. After thu-ty-five minutes I visited 

 the box, but found nothing had arrived. I then left her for 

 ten minutes more, and retiuned, with the same result. Dui*- 

 ing this expedition I again carefully examined many webs of the 

 larva?, and took a quantity of the mucus from them home and 



