191.S.] 89 



nutans) growing in fair abundance on Open Brasonose Conunon. A small 

 series was the reward of sweeping for an hour or two on July 21st last. 



T. acuticornis Lw. — I have only met with this species on one 

 occasion, August 10th, 1910, when a nice series was boxed from the 

 heads of the woolly-headed thistle {Ciiicns eriophorns). A fine patch 

 of this beautiful plant was growing in abundance in an old disused 

 quarry, near Wood Farm, Cowley. 1 found that searching the heads of 

 the thistle proved more effectual than sweeping. The flies were all boxel 

 from the exterior of the woolly receptacle, the insects' pale colour aiding 

 them considerably in their resemblance to the envii-onment. 



Urojyliora sohtifialis L. — A good series of this beautiful fly was 

 secured during July and August 1917 by regularly sweeping the musk 

 thistle {Carduus nutans), on Brasenose Common and Hogley Bog. The 

 best time was about the middle of July. This species, too, can be boxed 

 from the thistles if searching be preferred to the more laborious method 

 of sweeping. 



U. stylata F. — The most abundant species of the genus, being 

 found everywhere in the district, either by sweeping or searcliing tlie 

 spear thistle (Cniciis lanceolatus), during June and July. It was 

 especially abundant on Shotover Hill on July 7th, 1917. The hard, 

 nut-like galls formed by the larvae of the fly in the abortive seed-head 

 of the thistle are easily found during autumn, and these, if kept in a 

 fairly cool place, not too dry, will readily emerge the following yeai*, 

 sometimes four or five flies appearing from a single gall. The wing- 

 markings of this species vary considerably, even in individuals bred from 

 the same gall. 



TT. aprica Fin. — Has been taken b}- m}^ friend and colleague, Mr. J. 

 Collins, near Islip. 



TI. quadrifasciata Mg. — Also obtained by Mr. Collins at Water 

 Eaton. This and the preceding species have not, so far, been taken by 

 the writer, and I do not know the plant or plants fi*om which they were 

 swept. 



TI. cardui L. — This cui-iously marked fly is not met with so often as 

 one would expect, judging from the numbers of its well-known gall on the 

 stems of the (all too common) creeping thistle (Cniciis arvensis). It 

 seems somewhat local, but has been found throughout the district. The 

 insect should be looked for in June. Those desirous of breeding it suc- 

 cessfull}'' should allow the galls to mature before being gathered (as the 

 larvae pu])atc within the gall). Gathering should be deferred until late 



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