ON THE MILFOIL 



243 



Diptera Roots swollen near the stem. 



Trypeta guttularis Meigen 812 

 Syn. Carpotricha guttularis Meigen. 

 Connold, Plant Galls, p. 246. A. Muller, 1876, p. 18. 



, , Capitulum on the bud transformed in a hairy, subglobose, 



spongy gall, 5 to 20 mm. in diameter, white or tinted with 

 red. Plurilocular. 



Rhopalomyia ptarmicae Vallot 813 

 Trail, 1878. Houard, No. 5676, 5681. 814 



I, Flowers, leaves, and stems attacked. Galls about the 



size and shape of a hemp seed, green at first, becoming 

 reddish, black at maturity ; opening at the summit star- 

 like, with 4 or 5 rays. Interior lined with hairs,. and con- 

 taining a single yellow larva. The galls are either solitary 

 or coalescent, in the latter state sometimes forming a 

 bunch as large as a filbert nut at the base of the stem. 

 M. G. Imago, spring, II. (Plate XXXI.) 



Rhopalomyia millefolii H. Low 815 



Syn. Hormomyia millefolii H. Low. 816 



Connold, Plant Galls, fig. 327. Swanton, Knowledge, 817 



June, 1910. Houard, No. 5673, 5680, 5685, 5691. 818 



Homop- A little depression on the lower surface of the leaf, with 

 tera a raised area on the corresponding superior surface. 



Aphalara nervosa Forster 819 

 Scott, 1881^, p. 18. Houard, No. 5689. 



Nematoda Leaves and petioles swollen and distorted, bearing 

 globular growths about the size of a hemp seed. Solitary 

 or gregarious and coalescent, yellowish-green, becoming 

 brown. Each gall contains numerous eel-worms. June to 

 October. (Plate XVI.) 



Tylenchus millefolii F. L6\y 820 

 Connold, Veg. Galls, pis. 77, 97 (in the latter the galls 821 

 are wrongly ascribed to Khopalomyia millefolii) ; Plant 

 Galls, fig. 328. Houard, No. 5684, 5688. 



Achillea Ftarmica Linn. 112. Sneezewort. 

 Diptera Entire head of the plant transformed into a spongy, 

 hairy, subglobose mass, 30 mm. in diameter, white or 

 tinted rose colour, surrounded by numerous leaves. 

 Cavities numerous, containing many larvae. M. G. 

 Imago, spring, I. 



Rhopalomyia ptarmicae Vallot 822 



Syn. Hormomyia ptarmicae Vallot. 



Inchbald, 18610, p. 164. Connold, Plant Galls, p. 246. 

 Houard, No. 5706. 



