72 Transactions. — Zoology. 



same as in the early state. The mentum is small, globular, 

 and monomerous. 



Between the female and the bark, both in the early and 

 in the late adult state, there is a thin white waxy indusium, 

 which is sometimes fragmentary, but at others fairly complete, 

 with a pi'olongation to cover the tail. 



Second female stage not observed. 



Larva greenish, or yellowish, or sometimes slightly red. 

 Length, about -^in. Form broadly elliptical, distinctly seg- 

 mented ; margin minutely crenulated. Antennae short, with 

 six joints, of which the fourth and fifth are the shortest, the 

 rest subequal : on the last joint are several hairs, of which 

 two are rather long. Feet moderate ; the digitules are long, 

 fine hairs. There are two very minute anal tubercles, with 

 long setae. The dorsum bears two longitudinal rows of large 

 figure-of-eight spinnerets. 



The male pupa occupies the tube in the prominent gall 

 above mentioned, but between it and the tube is a white, thin, 

 elliptical, waxy test, which splits in half to permit the egress 

 of the adult. Often galls can be found containing only the 

 two empty halves of this test. The pupa appears to be ellip- 

 tical, brown, and flattish ; but the specimens observed w T ere 

 not in good order. Attached to one of them were the exuviae 

 of a larva, in which the antennae had only four joints. Per- 

 haps this may be a distinction between male and female 

 larvae. 



Adult male brown, with iridescent wings. Length about 

 ^Lin. The antennae are short, with only eight joints, of which 

 the first is short and round, the second longest, the rest 

 diminishing gradually : on the last joint there are four 

 knobbed hairs. Feet normal ; anal spike short. 



Hab. In Australia, on Casuarina sp. Mr. Froggatt has 

 sent me many specimens from Thornleigh, near Sydney. 



Although the very inconspicuous gall formed by this insect 

 (which indeed is almost entirely subcortical) differs consider- 

 ably from that of F. casuarina (1891), yet its generic position 

 is very clearly defined by the " tail," by the waxy indusium of 

 the adult female, and by the figure-of-eight spinnerets of the 

 larva. The male pupa forms a decided gall. The discovery 

 of this species is very satisfactory, as indicating the correct- 

 ness of my view in 189], when I decided that F. casuarina 

 might fairly form the type of a new genus. 



Many of the male galls of F. scmiocculla contained num- 

 bers of fat, white, soft grubs, which I presume belong to some 

 dipterous insect. 



At the risk of wearisome repetition, I cannot help again 

 asking the question : Can anybody suggest an explanation of 

 the burrowing powers of insects such as this ? Here is an 



