ANDRICUS RAMrLI. 69 



It is undoubtedly one of tlie most distinctive and 

 delicate galls of the oak. 



So far as my observations of this species have 

 extended, it appears that it may be found more 

 frequently on Q. sessiliflora than on Q. peduuculata. 

 On the continent, however, Q. i^tuhescens seems to be 

 the favourite tree. 



This interestino* and most attractive growth is one 

 which commands more than a passing notice from all 

 persons who see it for the first time. It has the 

 appearance of a tuft of Avhite cotton-wool, and among 

 the green leaves and yellowish catkins it looks 

 exceedingly pretty and dainty. 



These galls attain maturity of form very rapidly, 

 and the period during which they retain their pristine 

 beauty is also very brief; in sheltered positions it is 

 from five to seven days. Considerable care must be 

 exercised while gathering them. They are very 

 delicate, and any undue pressure will compress the 

 hairs and render it impossible to restore them to their 

 original form. Heavy rain will also disfigure them. 

 The hairs at first are more or less separate from each 

 other; about 15-20 mm. long, somewhat glutinous 

 and wool-like, and when in a mass are not resilient. 



The entire structure, or compound gall, consists of 

 clusters of cono^omerated larval chambers each of 

 which constitutes a true gall. The clusters vary in 

 number from two to ten, and contain about fifteen 

 larval chambers in each. It is from these clusters the 

 hairs grow, and being in close proximity to each other 

 unite to form an oval or globular-shaped mass of white 

 hairs, about the size of a walnut or a cherry respec- 

 tively. 



In drying the mass diminishes to about half its 

 original size. This is due to the contraction of the 

 hairs, which become convoluted and interwoven. The 

 colour changes to a yellowish-brown soon after 

 maturity, and the imagines then make their exit. The 

 galls occasionally develop from a leaf -bud. 



