Galls caused by the larvae of Cecidomyia tilicola Rud. 



on 



the flower-pedicles of Tilia europaea Linn. 



PLATE 121. 

 Synonymy of Insect. 



Habitat of the Common Lime-tree.— This tree occurs 

 throughout Britain in woods, parks, avenues, etc. It is 

 profuse in its foliage and flowers, and assumes handsome 

 and noble proportions. 



The Gall is formed by the presence of the larvae within 

 the pedicle of the flower causing it to swell to enormous 

 proportions. 



Position.— On the flower-pedicle. 



Manner of Growth.— Singly or in clusters ; sessile ; gla- 

 brous ; coalescent. 



Colour. — Green, greenish yellow, orange -yellow, suffused with 

 crimson. 



Average Dimensions of a Mature Specimen. 

 Length, 7 mm.; girth, 15 mm. 



May be sought during the months of June to October. 



The Growth is complete by the end of July. 



The Typical Condition of the gall is plurilocular. Usual 

 number of cells, 6. 



The Larv^ pupate in the gall. The imagines emerge 

 during August. 



The galls occur in three different situations : {a) at the 

 base of the peduncle, where it diverges from the mid-rib of 

 the bract ; {b) at the top of the peduncle, at the point from which 

 the pedicles branch oft" ; and {c) the typical position, as shown 

 in the specimens on the opposite page — vi:;. on the pedicles 

 themselves. Two examples of {a) may also be seen at the 

 bottom of the illustration. In the first case, no difference is 

 caused in the nature of the infloresence ; in the second, very 

 little, if any ; but in the third, the flowers are entirely abortive. 



The illustration is of specimens gathered at Midhurst, Kent, 

 by Mr. R. R. Hutchinson. 



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