248 THE ENTOMOLOGIST. 



bean, was then largely in excess of what it is now: it was 

 then from three to five in a bean ; and now the average 

 number, per bean, is certainly a decimal fraction of one. 

 Here is a crumb of comfort for the sufferers. — E. Newman.] 

 The Gall Midge of the Ash {^Cecidomyia hotularia, Win- 

 nertz). — It often occurs that, long before autumn, particularly 

 in dry seasons, the foliage of the common ash (Fraxinus 

 excelsior) shows signs of premature decay by turning sere 

 and yellow on certain sheltered branches, which eventually 

 shed their leaves much earlier than their neighbours. If we 

 ask the cause of this, we are generally told that the leaves are 

 blighted. But ''blight" is such a convenient term when we 

 want to gloss over our superficial knowledge of the diseases 

 of plants, that we have long made up our mind not to 

 be contented with this explanation. In the present instance 

 our observations extend over four years' occasional investi- 

 gations in Kent and Surrey. We meet with such unhealthy 

 branches on trees of all ages as early as July and August, 

 but it is in September that their yellow hue strikes us most 

 forcibly. For example's sake, we single out one limb, and 

 describe its condition as seen in September. Here and there 

 we see one intact leaf, standing out by its greenness, but'the 

 rest are more or less discoloured, and, moreover, distorted, 

 irregular in shape, and folded or crumpled up. We look for 

 a common mark, how to distinguish these disfigured leaves 

 from the normal ones, and we find it in a peculiar partial 

 thickness of the midrib, which, besides, exhibits a longitu- 

 dinal channel in many instances. Up till this time we have 

 only been viewing the upper surface of the leaves; let us, 

 therefore, inspect their underside as well. We raise the 

 branch up, and the cause of its blighted appearance is 

 explained. Every discoloured and disfigured leaf exhibits 

 on its leaflets a more or less slender swelling of the midrib or 

 of the stalk itself; in souie leaves the whole midrib, from 

 base to tip, is thus incrassated, and the lateral parts of the 

 leaf folded from edge to edge ; in others their basal part 

 alone is swollen up, and their anterior part more or less 

 aborti/^'c. These pod-like swellings or galls are covered with 

 a whitish or brown pubescence, and their juicy consistency 

 shows that they serve as receptacles, diverting the sap, 

 originally intended to supply the whole leaf; hence the sere 



