This very large stick insect is an adult female of a species without a common name but with the scientific name Phasma reinwardtii.  It is a large species from the forests of Papua New Guinea, where it spends much of its time in the canopy of the trees feeding on the leaves.

This particular individual measures more than 15cm in length and weighs in at 18 grammes.  Female stick insects are often larger than the male of the same species, and sometimes the size/weight difference is quite amazing!  This is certainly the case here, with the male weighing under 2 grammes despite being about 10cm long!  The pictures below show the female first and then the male, you can see that the male doesn't extend much past my fingers whereas the female is bigger than my whole hand!

The male's slender body shape and light weight allows him to fly, whereas the female is too heavy to get off the ground despite having well-developed wings.  The male is also a very attractive animal in his own right, as you can see below!!