84 THE ENTOMOLOGIST. 



then disengaging itself by process of growth, a few fine 

 shreds of tissue being noticeable drawn across the forming 

 cavity, from the outside of the capsule to the inside of 



Fig. 2. — Andmcus ci kvator. 



the containing hollow chamber, and then separated, this 

 being completely effected in the case noted in about five 

 days (from May llth to May 16lh). 



Looking at Cytiips galls of the oak (as most easily trace- 

 able) it appears that one species of Cynips causes one special 

 kind of gall, whether the oviposition is on different parts of 

 the tree, or whether several species deposit together in pre- 

 cisely coinciding position and circumstances. We see an 

 example of the former in the well-known currant-gall, 

 formed by Spathegaster baccarum, alike on flower-stalks 

 and on leaves;* and of the latter in some of the bud- and 

 bark-galls of the less-known species of AphilothrLv, where it 

 appears plainly shown that it is oviposition, not the part of 

 the tree attacked, that affects the characteristic of the gall. 

 The cells of Aphilothrix corticis and A. radicis n)ay be 

 found in precisely siuiilar circumstances in young bark ; 

 Andricus quadrilineatns with those at the base of the gall 

 of A. ramuli (the woolly-gall); or again in the case of the 

 artichoke-gall [Aphilothrix gemnue), occurring in the axil of 

 a leaf on a shoot bearing galls of Cyirips Kollari, and 

 similarly in the axils of the leaves iinmedialely above and 

 below; but with this, although the form of the gall (properly 

 so-called) appears constant, yet there are modifications in 

 what may be called the secondary part. 



* Even slioulil tin- altei'uatiou of generation betweeu Spathegaster 

 haccaruiH and Neuruterus lenticularis, wliich Dr. Adler considers to take 

 place, become a proved fact, this would in no way militate against tlie 

 constant correspondence of tlie gall and its insect, as under tliis theory the 

 change of one follows the change of the other. — E. A. 0. 



