56 
BRITISH GALLS 
covered, until it has obtained a sufficient size, and thus makes 
a habitation in which to pass its first winter. With the 
approach of spring the sap begins to flow again, and this 
probably supplies the larva with nourishment; it attains 
its most rapid growth at the time when the flush is greatest. 
It remains as a full-fed larva through its second autumn 
and winter, pupates in April, and the moth emerges at the 
end of May or early in June, thus occupying a period of two 
years in completing its metamorphosis.” In weakly trees the 
shoot above the resinous nest dies, and numerous lateral 
shoots appear just below it. Plate VII., Fig. 8, presents a 
reduced view of a gall; Fig. 9 is the moth, which is 
slightly less than 1 inch in wing expanse; Fig. 10 a 
longitudinal section of a gall, showing the larval cavity, 
half the actual size. 
Mompha decorella (Plate VII., Fig. 7) is widely distributed 
in England, and is frequent in some districts in the southern 
counties. Its principal food-plant is the Broad-leaved Willow 
Herb (Epilobium montanum). Barrett observed it in the 
Haslemere district in 1865, and published notes on the galls 
in the first volume of the Entomologist's Magazine. Fig. 6 
shows a gall, half natural size, on the stem of Epilobium 
parviflovum. It is fusiform, and about 20 mm. long. 
Augasma aeratella is confined to the south-east corner of 
England, and is rarely found in abundance. Shoreham is a 
well-known station for it. Messrs. Eustace Bankes and 
B. A. Bower have kindly sent me galls from that locality. 
Plate VII., Fig. 1, shows Knotgrass bearing the terminal 
pouch-like galls, natural size; Fig. 2, the insect slightly 
enlarged ; Fig. 3, longitudinal section of a gall, twice natural 
size. 
Nepticula argyropeza is widely distributed in England. It 
is a minute insect, only 6 mm. in wing expanse. Plate VII., 
Fig. 5, gives an enlarged view of it ; Fig. 4 shows its gall, a 
somewhat spherical swelling on the upper part of the petiole 
of an Aspen leaf, one-half actual size. 
