74 
BRITISH GALLS 
taeniopus and Oscinis frit are very destructive to cereals. 
Myopites inulae and M. Frauenfeldi cause the receptacle of 
the Fleabane and the Golden Samphire to become swollen 
and almost woody. As the galls are identical, and Mr. 
Collin says the flies have never been well differentiated, they 
are possibly forms of the same species. 
Economic Notes 
There are many destructive pests amongst the gall- 
causing Diptera. One of the worst offenders is the Hessian 
Fly, Mayetiola destructor Say, which causes swelling of the 
base of the haulm and sharp bending of the stem (just above 
the part containing the larva) of wheat, barley, and rye. It 
was first noted as a British insect by Miss Ormerod. A 
long account of it is given in her “ Manual of Injurious 
Insects,” and it also forms the subject of leaflet No. 125 
issued by the Board of Agriculture. It was prevalent in 
this country in 1886 and 1887, but, though still occasionally 
met with, it has not caused any serious damage since. It 
is said to infest Timothy Grass and Couch Grass in Russia. 
The larvae of Asphondylia pimpinellae F. Low cause the 
flower stalks and the seeds of the Common Parsnip to be¬ 
come swollen. 
A. Muller, in 1870, recorded in the seventh volume of the 
Entomologist's Monthly Magazine the occurrence of galls 
caused by Asphondylia dorycni F. Low on Dorycnium suffru - 
ticosum Vill. ppentaphyllum Scop.). They were about 6 mm. 
long and 3 mm. in diameter, were situated at the junction 
of the lateral branches, and were covered with long white 
unicellular hairs. The larvae pupated in the galls. 
Westwood recorded, in 1885, the presence of galls on the 
roots of orchids ( Dendrobium sp.). They were situated on 
the radicle, and attained the size of a wheat grain, which 
they also resembled in shape. The ovoid cavity contained 
an orange-yellow larva. This Cecid was not determined. 
On the Continent Cecidomyia cattleyae Moll, causes galls of 
