Galls caused by the larvae of Hormorayia piligera Lw. 



on 



the leaves of Fagus sylvatica Linn. 



PLATE 9S. 

 Synonymy of Insect. 



Honnomyia annulipes Hartig., Wtz. 

 .. piligei'a Theobald. 



Cecidomyia piligera Moslcy. 

 Habitat of the Common Beech.— A large and tali tree of 



majestic and noble proportions. Grows in woods and forests 



in every part of England, where it is extensively planted. 

 The Gall is formed by the deposition of an ovum in the upper 



surface of the leaf causing a pilose, cone-shaped structure. 

 Position. — On any part of the leaf, but principally near the 



mid-rib. 

 Manner of Growth. — Gregarious ; pilose. 

 Colour. — Yellowish, deepening to orange, ultimately reddish 



brown. 

 Average Dimensions of a Mature Specimen. 



Height, 4 mm. ; girth, 8 mm. 

 May be sought during the months of July, August, and 



September. 

 The Growth is complete by the end of August. 

 The Typical Condition of the gall is unilocular and 



unilarval. 

 The Larva pupates in the gall. The imago emerges during 



the spring. 



In the lower part of the illustration the under surfaces of 

 three leaves are shown, the slightly raised pimples indicating 

 galls on the upper surfaces. Five leaves in the upper part of 

 the illustration show young galls on their upper surfaces. At 

 Battle, Sussex, on August loth, 1900, the author gathered a very 

 fine collection of galled leaves, two of which are worthy of note. 



No. I, 85 mm. long, 48 mm. at widest part, supported 

 thirty-four separate galls. 



No. 2, 97 mm. long, 60 mm. at widest part, supported 

 forty-three separate galls. 



The illustration is of specimens gathered at Eastbourne by 

 the author. 



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