J. T. Wadswortii 147 



Food-flants. 



As regards the food-plants Schiner (1858) remarks that : 



" The larvae live in the flovver-heads of Carduus nutans L., crispus L. 

 and acantlwitJes L. ; they are also found in those of Cirsinm lanceo- 

 lafuni L., Centaurea scabiosa L. and montana L., and on other Cynaroi- 

 deae " ; F. Low (1866) recorded Centaurea paniculata L., as a food-plant 

 of the larvae, and Fitch (1872) recorded this species from galled flower- 

 heads of Serraiula tindoria L., collected in Suffolk. In a later paper 

 (1879) this observer remarks that in 1872 he added to the list of [British] 

 gall-making Trypetidae, Urophora solstitialis L., " which deforms the 

 ovary of the common knap-weed (C. nigra) into a hard, woody, but 

 only tactilely noticeable gall." 



This is the first record which I have been able to find of the occur- 

 rence of this species on Centaurea nigra. Curtis (1860) refers to U. sol- 

 stitialis under the name Tephritis solstitialis as being abundant on thistle 

 blossoms during the summer, he does not state, however, that he bred 

 the fly from thistles. Connold (1901) and Swanton (1912) both give 

 C. nigra as the food-plant of the larvae of this species ; Prof. Trail 

 informs me that in Scotland C. nigra alone is known as the food-plant. 



It is noteworthy that none of the continental authorities, whose 

 writings I have been able to examine, record Centaurea nigra as one 

 of the food-plants of these larvae ; on the other hand, with the single 

 exception of Fitch's record of Serratula tinctoria referred to above, all 

 the records of its occurrence in this country that I have been able to 

 consult, state that Centaurea nigra is the food-plant of the larvae here. 



Many of the recorded continental food-plants are equally common 

 in this country, whilst Centaurea nigra is common on the continent, 

 and it is worthy of remark that there appears to be this difference in 

 the habits of the larvae here and abroad. 



The larvae of a closely related species, Urophora quadrifasciata, are 

 recorded as feeding in the flower-heads of Centaurea nigra (Loew, 

 Schiner) ; and according to the account of Dufour (1857) the life- 

 history of this species and the effects produced by the larvae on the 

 host-plant, are very similar to those of U. solstitialis. 



There was just the possibility therefore, that I might be dealing 

 with this species {U. qxadrifasciata). Through the kindness of Mr J. E. 

 Collin, I have had the opportunity of examining two continental speci- 

 mens of U. quadrifasciata from Bigot's collection, and there is no doubt 

 that the specimens reared here from Centaurea nigra are distinct from 



