88 [April. 



Tl\e first was taken June 19th, 1915, the second on June 30th, 1917. 

 Care should be taken that this species is not passed over for A. lieraclei, 

 which it closely resembles, es2)ecially in the net. 



Spilograplia zoe Mg. — Occurs sparingly, always on thistles, chiefl}^ 

 Cnicus Janceolatus, at various localities in the district, the University 

 parks, Shotovei- Hill, and Headington Wick Copse. End of May 

 and June. 



S. artemisiae F. — Until last season (1917) this fly had only occurred 

 very sparingly, probably because I had not hit upon the right time or 

 place. On July 2Sth, in and around Hogle}' Bog, it was taken plenti- 

 fully by sweeping mugwort {Artemisia vulgaris). My other dates 

 extend from Mav to Aus^ust. 



Trypeta onotropTies Lw. — One individual was swept from the mai*sh 

 thistle (Cnicus paliistris), near Bayswater Mill, on July IJrth, 1917. 



T. cornuta F. — This species was extraordinarily abundant during 

 the past season, and could have been obtained in hundreds during July 

 by sweeping the large knajDweed {Centaurea Scahiosa). It was especially 

 common on and around Shotover Hill, but also occurred all over the dis- 

 ti-ict. The smaller black knapweed (C. nigi-a) was also swept whenever 

 met with but did not yield the fly. This is a most beautiful insect when 

 alive, of a lovely pale green colour, w^hich soon fades after death. 



T. tussilaginis F. — One specimen by sweeping in a rough clay-pit, 

 Shotover Hill, August 11th, 1917. There was plenty of coltsfoot growing 

 all over the pit, but I could not decide whether the specimen came off 

 that plant, for persistent sweeping failed to yield another. 



T.Jiorescentiae L. — This elegant little fly is evidently attached to 

 the marsh thistle (Cnicus j^alustris). A rough pastm-e-field on the north 

 side of Shotover Hill is much overgrown with this tall thistle, the flower- 

 heads of which, when swept on July 7th, 1917, yielded a fine series. 

 Other species of thistle growing in the same field were also tried, 

 but entirely without success. A week later, near Bayswater Mill, 

 Headington, the marsh thistle was again tried and a few more 

 examples taken. * 



T. colon Mg. — -This species, so far, has proved rather scarce here. 

 About a dozen specimens have been taken by sweeping the knapweed 

 {Centaurea Scahiosa), during July, on Shotover Hill and Hogley Bog. 

 Somewhat variable in colour. 



T. serratulae L. — This, again, is not a plentiful species in the dis- 

 trict. It has only been obtained by sweeping the musk thistle {Carduus 



