Galls caused by the larvae, nymphs, and imagines of 

 Phyllocoptes acericola Nal. 



on 



a leaf of Acer pseudo-platanns Linn. 



PLATE 73. 



Synonymy of Mite. 



Volvulifex aceris Amer. 

 Ceratoneon vulgare Bremi. 

 Phytoptus aceris Mur. 



Habitat of the Sycamore.— Distributed throughout Britain 

 in gardens, private grounds, plantations, and parks. 



Position of the Galls. — On the upper surface of the leaf 



Manner of Growth. — Gregarious ; glabrous ; glossy ; more 

 or less globular. 



Colour. — Orange -yellow, bright carmine, purple. 



Average Dimensions of a Mature Specimen. 

 Height, 2 mm. ; girth, 3 mm. 



May be sought during the months of June to October. 



The Growth is complete by the end of August. 



These galls are well known to all who observe the sycamore- 

 tree. They appear in very large numbers, sometimes so 

 numerous as almost to cover the leaf It is not unusual to 

 find as many as 650 on a leaf of average size. What may be 

 lacking as regards size, is partly supplied by their excessive 

 abundance, but mostly by the brilliancy of their colouring. A 

 section of a gall seen under magnification shows the interior 

 well filled with long hairs, amongst which the mites swarm in 

 large numbers. 



The gall is also figured by Murray, " Economic Entomology," 

 P- 357- 



The illustration is of a specimen gathered at Hastings by 

 the author. 



178 



