74 BRITISH GALLS 



taeniopus and Oscinisfrit are very destructive to cereals. 

 Myopites inulae and M. Frauenfeldi cause the receptacle of 

 the Flfeabane 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. Miiller, 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. (pentaphyllum 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 MolU causes galls of 



