1918.] 87 



TRYPETIDAE FROM THE OXFORD DISTRICT, WITH NOTES ON 

 THEIR TIME OF APPEARANCE AND FOOD-PLANTS. 



BY A. H. HAMM, F.E.S. 



It is long since any special reference to the time of appearance and 

 the food-plants of the Trypetidae has been published in the pages of 

 this Magazine,* and I think that a few notes on the Oxford species may 

 be of some assistance to those who take a delight in these interesting 

 and beautiful flies. Some of the species are to be had in abundance by 

 sweeping or searching at the right time their respective food-plants ; or 

 again, the galls, leaves, etc., containing the larvae, may be gathered and 

 the occupants bred in due course. Then, too, the interest taken in col- 

 lecting or breeding the commoner species will inspire the naturalist to 

 search for some at least of the rarer and little-known forms, and thus in 

 time we may hope that the habits and food-plants of all our native species 

 may be known and recorded. It is with this object in view that I am 

 induced to write the following rough notes. 



Nearl}' all the following species were taken within three to four 

 miles from the centre of Oxford, some at least within the boundary of 

 the City itself. 



Aciura rotundiventris Fin. — This rare species was taken as long 

 ago as June 23rd, 1832, by the Eev. A. Matthews, at Weston-on-the- 

 Green, near Oxford, t I have not met with it so far. 



Acidia cognata W. — A few taken in various years, always at the 

 end of June, resting on the upper-side of alder-leaves, Hogley Bog, near 

 Cowley, Oxon, and several in a garden on Shotover Hill, on lilac-leaves, 

 July 1, 1917. 



A. heraclei L. — This is the well-known parsnip and celery fly, but 

 away from gardens it is not at all plentiful. It can, however, usually be 

 swept from Heracleum. My friend Mr. H. Britten bred it in large 

 numbers during July 1916, from the blotched leaves of parsnips growing 

 in his garden at Headington. Similar blotched leaves were present in 

 almost every patch of parsnips looked at in gardens and allotments all 

 over the district, but I believe it does little or no harm to this useful 

 vegetable. 



Gonyglossum iciedemanni Mg. — I have only met with this species 

 on two occasions, both on Shotover Hill, probably swept from Heracleum.^ 



* E. C. Bradley, Ent. Mo. Mag. 190], p. 9. 

 t C. W. Dale, Knt. Mo. Mag. 1904, p. 212. 

 I G. ttiedimanni is tj be found occaBiunallj in numbers on Bryonia d.oka.—J, E. C. 



