58 DESTRUCTIVE INSECTS OF VICTORIA : 



" Perhaps the most remarkable of all the gall-forming 

 insects are the species of Frenchia, all of which attack 

 the Casuarinas, or She- oaks. There are two species 

 now known, one from Sydney, where it appears to be very 

 rare, the other from Victoria and Tasmania ; the latter 

 species is known as Frenchia casuarina, and frequently 

 kills branches of She-oaks. Its larvae, when young, are in 

 appearance much like those of other members of the family, 

 being provided with three pairs of legs, a pair of compound 

 eyes, and a pair of antennae. After leaving their mother 

 gall, they wander over the bark, and finally settle down. 

 Here they cause galls to form, the galls in time completely 

 covering them. The galls continue to grow, and eventu- 

 ally from the middle of each gall a cylindrical woody 

 growth appears, which may be readily detached. 



" Meanwhile, changes have been taking place in the 

 insect itself ; it loses its legs, antennas, and eyes, and even 

 its mouth parts (henceforth receiving its nourishment 

 through its skin by the process known as osmosis), and 

 appears as a little brownish object of irregular shape, but 

 having a small node at its lower end, and a sort of thick 

 tail at one side. As growth continues, the tail becomes 

 thinner and increases in length, extending almost the whole 

 length of the woody growth ; its bottom also becomes 

 saucer-shaped, but still with the small node which is fitted 

 into a depression in the wood ; it is doubtless at this 

 stage that pairing takes place. Later on, the tail collapses, 

 bends over, and appears fitted to a remarkable cap, which 

 is joined to the body by an irregular suture, much as the 

 sutures of the bones between the human skull. The body 

 itself is now shaped like a wad, and, on removing the cap, 

 the top can be seen to be completely covered by fine 

 concentric rings, with a small opening in the centre, from 

 which the young can be nearly always seen escaping. 

 A heavy coating of white mealy substance is always 

 attached to the wall of the enclosing gall, while the insects 

 are healthy, but when these are attacked by parasites, as 



