THK ENTOMOLOGIST. 



99 



Fig. 9. 



a. Andricus nodvli. 



b. A. SECTION. 



Andricus noduli. — This liltlc gall, like 

 the preceding, is invisible from the ex- 

 terior, being embedded in tlic bark of 

 Quercus pedunculata and Q. pubescens. 

 A small spherical or oval swelling is 

 observable on the young shoots of the 

 Quercus pedunculata, raising the bark 

 or rind from 1'5 millemetres to 2 mille- 

 metres in diameter, and beneath this 

 swelling is situated the gall. On Quercus 

 pubescens the swelling occasioned by 

 this gall is still less perceptible, on 

 account of the tomentum on the surface, 

 and sometimes it is entirely absent. It 

 is best to look for these galls at the end 

 of September, when the perfect insect 

 emerges : after some have escaped, and 

 have left little circular holes in the rind, 

 it is easier to watch -the remainder, as 

 they usually follow in the course of a few 

 days. The circular aperture, made by 

 the perfect insect on its escape, is 

 scarcely half a millemetre in diameter. The oval gall, only 

 1'3 millemetre in length, is situated either between the bark 

 and the wood, or in the wood ilself, and is placed longitudi- 

 nally with the twig : it is while, and closely surrounded by 

 wood and bark ; it has a thin covering, and contains one 

 larva cell. On the twigs of Quercus pedunculata the 

 externally-visible swelling subsides after the escape of the 

 perfect insect, and becomes a blackish coloured speck, with 

 a circular aperture in its middle. In Quercus pubescens you 

 are frequently unable to detect the swelling at all, and if any 

 unevenness has existed it remains after the perfect insect has 

 made its escape, and the surface of the bark does not change 

 colour. This gall is occasionally on leaf-pods and on petioles. 

 It is probable that the gall named C. Turionum, with which 

 I am unacquainted, belongs to this species. — G. L. Maijr. 



Mayr mentions three inquilines inhabiting the galls of 

 Andricus nodnli : Ceroptres aiator, Hart., Sapholytus con- 

 natus, Hart., and Synergus a])icalis, Hart. The first appears 

 in May and June of the second year; the third in May of 

 the second year. — Francis lialker. 



