308 THE ENTOMOLOGIST. 



unfastens the door, and goes out; and if it has been destroyed 

 by a cuckoo-fly, it is probable that the latter has the instinct 

 to escape in like manner. Supposing the first Osmia to 

 return unexpectedly, and to find a Chrysis, a Fcenus, or a 

 Leucospis, as the case might be, in its home, then there 

 would be materials for another page in the history of the gall, 

 and for an additional account of the agreements or disagree- 

 ments in the little nest. 



Many changes thus take place in a gall. Its first state, 

 which is common to all galls, represents, in a small compass, 

 the control of vegetation by insects. The second period, 

 which is partial, shows the check of some insects by others, 

 and in two ways : by outward or by inward agency, — by 

 starvation without, or by consumption within. In the third 

 period, the vegetation -eaters have ceased, and the carnivorous 

 race alone survive, A new order begins when the gall has 

 ceased to grow around its inmates, when the aboriginal 

 Cynips has gone, and when the Osmia has taken possession 

 and has provided stores for its young ones. The gall is 

 lastly tenanted by mites, and is afterwards reduced to earth 

 by the other elements. 



Francis Walker, 



Supplementary Note on the Genus Acentropus. 

 By J. W. Dunning, M.A., F.L.S. 



By way of supplement to my notes (Trans. Ent. Soc), 

 I beg to give a few additional references and localities for 

 Acentropus. To the list of localities there may be added: — 



England (Sheerness, J. t/. Walker: Veckha^m, Cowley). 

 Scotland (Loch Leven, Kinross, and Loch Gelly, Fife, 



Syme). 

 Sweden (Ifosjdn, Ringsjon, Wombsjon, Farhult, Wal- 



lengren), 

 Belgium (Forest of Linthout, Andries ; Brussels, Fologne), 

 Holland (Overween, and Texel, Ritsema). 



And to the list of authors : — 



1859. Fologne, Ant. Soc. Ent. Belg. iii. 134. 

 1870. J, „ xiii., Comptes Ren» 



dus, p. xxxvi. 



