70 AN ACCOUNT OF BRITISH FLIES. 
C. pleridis, Mill. = C. filicina, Kief. 
Imago unknown. Miiller describes the larvee as reddish in colour, 
living in the “rolled” and “laid down” leaflets of the fronds (of 
Pteris). One larva in each leaflet. The leaf-rolls are at first green, 
then they become cigar-shaped and reddish, and as soon as the 
larvee pass to the earth they become black. Perris* describes the 
habits as follows: “Au mois de juin, en observant avec soin les 
feuilles de la grande fougtre, Pzeris aguilina, on remarque ¢a et 1a 
des folioles roulées en dessous d’un peut cété, la partie roulée étant 
ordinairement brunatre, ce qui la rend plus apparente. Si on la 
déroule avec précaution on met 4 découvert une larve Cécidomyie 
d’un blanc rosé.” 
C. quercus, Lw. 
(c. roboris, Hardy. 
C. reapertens, Bach. 
\c . inflexa, Rudow. 
Jmago unknown according to Bergenstamm. Hardy gives an 
- account of this in the “ Scottish Gardener,” iii, 1854, which I have 
been unable to obtain. The larve are said to live chiefly in the 
leaves of the oak ; the lobes of the leaf being folded and laid down 
on the under side, forming a hollow for two or three larve. The 
folds are paler than the leaf. The larve pupate in the earth. 
C. thalictri, Traill. 
As far as I can make out this only appears to have been mentioned 
by Low.t Bergenstamm says, “Imago unbekannt.” The larve 
live in the deformed fruit of Zhadictrum. 
C. tilie, Schrk. = | is AaPCROIERS \ Macq, 
C. pustularis, Bremi= - 
C. excavans 
The zmago likewise unknown. Concerning the larve Walker 
says: “In June the galls} of C. “#/ie are not uncommon on the 
young shoots growing from the stumps of lime-trees by the banks of 
the Wye, near Chepstow. They are round or oblong, green on one 
side, bright red on the other. Some of them contain more than 
twenty separate cells, each inhabited by one larva. The latter is 
about one line of length, of a bright yellow colour, and has the 
faculty of leaping, like the larva of Piophila. It is full grown in the 
third week in June.” 
Bergenstamm says: ‘ Die Larven leben gesellig in dem nach oben 
eingerollten Blattrande von Zi/ia europea.” 
* Tr. Ent. Soc. Fr., 1870, p. 180. + D. B. iv., 1850, p. 30. 
t Ins. Brit. Diptera, iii., p. 130. Bremi in his monograph figures the galls of 
C: tiliacea on the leaf of 7. Zuropea in several stages. 
