250' 



closely allied Seville or bitter orange, Citrus Aurantium, var. Bigaradia, 

 is never attacked, but always th >ugh on the same ground exhibits a 

 much more vigorous growth than the sweet orange, f n every case the 

 characteristics appear to be the same. The trees are more or less hollow, 

 in extreme cases supported by only from one-half to two-thirds of the 

 bark with little of the inner wood remaining. This removal of the 

 wood extends a 'so to the larger branches. 



It appears that the principal destruction and removal of the wood is 

 "being carried out by means of the different kinds of ants, principally 

 the white or Duck ants (Termites) and the black ants. The ants however 

 in all probability are not the primary cause of the damage ; the trees 

 are first exposed to their activity by the removal of the bark, due to the 

 -action of the larvae of the longicorn beetle, and also, as mentioned below 

 by the careless destruction of the branches. 



Description of the Beetle. 



The beetle is one of the tribe of the Longicornes recognised by their 

 long antenna?, and by their large broad heads. This species is distinguish- 

 ed by the light silvery colour of its dorsal surface, and by having three 

 small dark tubercles on the dorsal surface of the thorax, The wing covers 

 have two small protecting spines at their posterior angles, the outer one 

 being the larger ; a small dark area produced into a line divides each 

 transversely into an anterior two-thirds and a posterior third. 



The larva is about half an inch in length, of a very light cream 

 colour, except the jaws and first seg-nent, which are a dark horn colour. 

 The body is broadest in front, narrowing gradually behind, and slightly 

 thickening again towarks the end. The dorsal part of each segment 

 has an oval area differing from the remainder. The sides of the body 

 have numerous finehai s. 



The pupa is of the well-known longicorn form, somewhat resembling 

 the adult, but light in colour, and with the large antennae at first 

 folded backwards down the sides of the body, but again turned and ly- 

 ing on the ventral surface. 



The action of the beetle is as follows : — 



The female lays her eggs upon the bark of the tree— the time of 

 the year when this occurs, and other details still require investiga- 

 tion. ^yhen the larvae are hatched, they eat their way through the 

 bark to the outer part of the wood. It is here, between the bark and 

 the new wool, that the boring larva live? for a considerable time and 

 undergoes its changes into the pupa which finally gives rise to the per- 

 fect beetle. 



Tae borer makes long tortuous shallow tunnels inside the bark and 

 in the new wood, giving rise to a great amount of dry powdery matter. 

 The effect of this tunnelling and d ?struction of the tissues between 

 the bark and the wood is that the former very readily separates from 

 the trunk. Quite large patches of the bark can be easily stripped off, 

 when the larva itself and its resulting shallow channel in the superfi- 

 cial part of the wood can be observed. 



In some places the larva has made oval depressions in the wood and 

 in tli3se the pupa stage is passed through. 



It is doubtful ho vever, to what extent this exposure by the 'Boiera 

 of tho woj:1 to th? an*;s is serious as compared with the wilful dimi^e 

 to large stems in gathering the oranges. It would appear in many 



