430 



ME. A. MtTLLER ON A CHINESE ARTICHOKE CALL. 



fostered, as tlio latter is, by man ever more and more extending 

 the area of action in the destruction of timber and consequent 

 growth of copses. Early in summer the female deposits its eggs 

 in the axillary fruit-buds ; in doing so it shows a decided pre- 

 ference for stunted or otherwise unhealtliy bushes or undergrowth ; 

 but where its numbers are once great, full-grown trees become 

 equally liable to infection. Each infected fruit-bud gradually as- 

 sumes the form of a hop-bloom or artichoke-like excrescence, con- 

 sisting of a series of elongated squama3 (representing tlie con- 

 verted cupule) and centring on a short woody basal axis, the 

 top of which is occupied by tlie stunted acorn. The squama? 

 generally conceal the acorn, which in this condition is only G-7 

 millimetres in length, with a diameter of about 3 millimetres. By 

 the end of September or beginning of the following month, the 

 acorn having done duty for an " inner gall," drops out of its folia- 

 ceous covering. If it be examined at this time, the interior will 

 bo found to bo converted into a spacious cell filled by the large 

 white fat larva of the Cynips. In spring tliia larva changes to a 

 sculptured pupa, which in early summer assumes the perfect 

 winged state and then quits the acorn. In cases where a para- 

 sitic Ilymenopteron has deposited its egg in the cynipideous 

 ogg or very young larva, the acorn remains very small (seed-like), 

 and but seldom preserves its normal shape. 



Eeaumur knew these galls, and has described and figured 

 them (Memoires, t. iii. p. 463, tab. 43 & 44), and has been fol- 

 lowed by numerous other observers ; but I have ventured to refer 

 to my own observations in preference, so as to bring out the salient 

 points between the European and the Chinese species. I dismiss 

 the notion of calling this latter gall an " oak-apple ;" the two 

 productions have not the slightest resemblance. 



Turning now to its affinities with the '\galle en articJiaut" of 

 Eeaumur, I venture to call attention to the following points. 



European form. 

 On Quercus pedunculata, sessili- 

 flora, and pubescens ; prefers young 

 copsewood and stunted trees. 



Exceedingly common. Axillai-y, 

 sometimes at extremity of twigs. 

 Shape of an artichoke or foliaceous 



Chinese form. 



On "Ta'ing kang,'^ an oak with 

 light-green leaves, in outline like 

 those of a slmllow-lobed form of Q. 

 robur ; on trees kept artificially in 

 the copse state. 



" Found frequently developed." 

 At extremity of twigs. "Green ball," 

 but figured as a foliaceous cone. 



