Galls caused by the larvae of Diplosis loti De Geer 



on 



the flower-heads of Yicia sepium Linn. 

 PLATE 122. 

 Synonymy of Insect. 

 Tipula loti De Geer. 

 Cecidomyia loti Meigen. 

 Diplosis loti Theobald. 



Habitat of the Bush-vetch. — Plentiful on roadside banks, 

 in hedges, woods, and shady places throughout Britain. 



The Gall is formed by the larvae arresting the development 

 of the blooms and further growth of the stem. 



Position. — On the flowers. 



Manner of Growth. — Seldom more than one on a stem ; 

 pilose. 



Colour. — Greenish white. 



Average Dimensions of a Mature Specimen. 



Height, 1 6 mm. ; breadth, lo mm. ; girth, 30 mm. 



May be sought during the months of June to October. 



The Growth is complete by the end of August. 



The Typical Condition of the gall is multilarval. 



The Larv^ pupate in the ground. The imagines emerge 

 during the summer. 



The galled flower-heads of this plant may easily be mis- 

 taken for partly expanded flower-clusters. It will be found, 

 however, upon taking the flowers apart, that the numerous 

 larvae are securely ensconced within the cluster, feeding upon 

 the young and tender inner portions of the galled growth, 

 causing a cessation of expansion and premature decay of the 

 affected parts. 



The illustration is of specimens gathered at Hastings by 

 the author. 



278 



