ERRATA. 
Page 12, line 18, read spores for pores. 
‘* 16, line 12, read its for it. 
‘* 18, line 13, read 25 mm. for 2.5 mm. 
‘* 19, line 33, read mushrooms for mushroons. 
‘* 20, line 25, read infected for affected. 
‘* 27, line 1, read forest for forets. 
‘* 80, line 13, read aphids for appids. 
‘* 80, line 27, read Aphidius for aphidiust. 
‘* 122, line 1, read trees for treee. 
