JAMES BURTON ON A SPECIES OF ALEURODES. 11 



with exceedingly small scales which are fastened to the membrane 

 with a ' quiir as in the moths. When the fly is ready to deposit 

 her eggs, she selects a depression in the under side of an outer 

 cabbage leaf, and then lays from six to twelve dark- coloured eggs 

 in a group, while all around are strewn scales from the wings and 

 body. And yet the fly looks none the worse ! What happens 

 next is not quite clear, but a white fringe appears all around the 

 egg which fastens it to the leaf ; and upon turning it over I find 

 a tiny grub underneath, furnished with six legs, each armed with 

 a bent claw and a long stiff hair. The abdominal segments can 

 just be distinguished. From the thorax (?) projects a long, 

 straight sucker, which is driven deep into the leaf. I am not 

 quite sure whether the insect uses its egg shell for its first covering. 

 or whether it makes a scale ; but in a day or two the fringe dis- 

 appears, and the grub and its covering grow rapidly, until it looks 

 like a tiny Brazil nut, with the sharp edge upwards. Then one 

 day the ' nut ' splits along the edge and the perfect imago emerges. 

 During the time the grub was feeding it moved only about half 

 an inch from the spot where was laid the egg from which it de- 

 veloped. This fly is known as the Cabbage Powdered- wing Fly — 

 Aleurodes 'proletella.^^ 



This description tallies in most respects with what I have 

 observed. First, however, it may be said that the mealy substance 

 does not consist of scales with a quill as in the moths. I have 

 been very careful in the matter ; the mealy substance consists 

 of very short curved rod-like pieces. One might almost consider 

 them to be minute rods of wax forced out from pores and 

 curving in the process. There was nothing like a scale or a quill 

 to fasten it. In A. hrassicae the egg was a short cylinder slightly 

 curved with rounded ends, pale yellow in colour, with a darker 

 orange spot at one end. The young larva has legs, antennae, two 

 pink eyes, some few hairs or bristles but not of great length ; it is 

 of a pale transparent yellow with an orange-coloured patch, seg- 

 ments just visible ; it moves feebly, and probably does not move 



