Coccus affecting the Orange. IJ 



of produce. That orange crops have been injured by this 

 insect is no new fact to bring before yon. 



In 1843 the ravages by the Coccus, of the orange trees, 

 had been so extensive as to cause the loss of the entire 

 produce in one of the Azores, and the evil rapidly extended 

 itself to the other islands, so that the whole injury done 

 appears to have been the work of three years only. 



The insect belongs to the same family as that which yields 

 the cochineal dye (Lac) ; and is commonly recognised as 

 the scale insect upon green-house plants. Last summer I 

 noticed a few of these scales on a piece of shaddock-rind, 

 which I kept for examination ; but this winter has supplied 

 me with a more abundant crop than I remember to have 

 seen; and some lemons, also, present a few on their surface ; 

 but whether the disease is on the increase or not I am 

 unable to state. 



The fruit is found sometimes fully covered over with 

 circular scales, of a dark reddish yellow hue ; each scale 

 presenting a slight, nearly central elevation, with a light- 

 coloured margin : it can be readily detached by the point 

 of a needle, or the scales come off in numbers on peeling 

 off the rind. They should be transferred to a glass slide, 

 with that side uppermost which was in contact with the 

 orange, and moistened with a drop of water, and covered 

 with thin glass in the usual way, they may then be examined 

 under the microscope. 



Within the round scale may be seen a yellow or amber- 

 coloured animal, which, at first sight, it is difficult to 

 recognise as such, especially as the insect is likely to be met 

 with in varying conditions : the usual form is that of a 

 rounded one, with a deep notch on one side, while the 

 border presents a thickened margin, and sometimes exhibits 

 a number of leg-like appendages. The nearly transparent 

 shell or case of the insect will be seen to be very delicately 

 striated in most parts, an appearance which is apt to be lost 

 whenever the fluid applied to it comes completely into 

 contact with the surface. The portion which presents the 

 notch appears to be the hinder or tail-end of the insect, and 

 is likely to be taken for its head, which, I believe, is indi- 

 cated by the presence of three setae, which in some specimens 

 can be seen to spring from that; portion which occupies the 

 centre of the disk, and is of a yellower colour. On either 

 side of this part may be seen two points, which appear like 

 openings for respiration, or what are technically called 



