Notes

Other Common Names
Common Imperial Blue; Imperial Hairstreak

I'd been wondering why this species is often called the Common Imperial Blue, since I had never seen one anywhere. Then I spotted a very tattered specimen feeding from flowers in the Ingleburn Recreation Reserve near my home. When I read up about this species, the books said they lived gregariously in very localised colonies, so the next chance I got I went back to that same spot and waited. I soon saw another specimen, and by following it I found the colony. There must have been about two hundred individuals gathered in a small area.

They were exhibiting all the behaviour noted in the books :

They were very gregarious
The larvae and pupae were attended by ants
The larvae and even pupae were gathered together
Males would sit by pupae, hoping to mate with a female as soon as she emerged.
Mating would begin even before the female's wings had expanded (talk about child brides!)
The colony was based around a group of juvenile Acacia bushes, mostly under 1 metre tall

Sightings
For over a year the only place I found this species was in the Ingleburn Reserve, off Bensley Road. I first saw on there on 31/03/2004. I saw them every time I went to that site in April 2004, in many places around the reserve. (It's strange how once I'd found them in one spot I kept on seeing them all over the reserve, even in the car park.) By the end of April they were noticeably fewer in number, and most of the individuals to be found were rather battered.
I then saw no sign of them until late October 2004, when I saw some larvae and pupae, again in the Ingleburn Reserve.
In early November 2004 I saw a few adults around the Reserve, though nothing like as many as the previous autumn.

In the summer of 2005/6 I found a lot of these butterflies at various places in the Blue Mountains National Park at Glenbrook.