SILVER -Y MOTH, 31 



Though the Colios edtisa does not rank amongst "injurious insects," 

 still it certainly appears that a butterfly of which the caterpillars, when 

 under supervision, are found "to eat voraciously," to " cat white trans- 

 parent blotches on the leaf," or again, to " consume a deal of food," 

 may prove to be an infestation requiring attention. 



Silver- Y Moth. Plusia gamma, Linn. 



\ 



Plusia gamma. 

 1, eggs; 2, caterpillar; 3, chrysalis in cocoon; 4, moth. 



The Plusia gamma, or Silver-Y Moth, is an exceedingly common 

 kind, and on the Continent of Europe, where its occasional great out- 

 breaks are more frequent than with us, it is sometimes almost over- 

 whelming in its ravages to various crops. Amongst those particularly 

 liable to attack, cruciferous plants, as Turnips and Cabbage ; legu- 

 minous plants, as Peas, Beans, and Clover (but iiot Lentils) ; and 

 Sugar Beet, are especially noted. Flax also is such a favourite food, 

 that the " Flax Moth " is one of its Continental names, as well as that 

 of Sugar-Pea Moth, and the name of Beet Moth is also sometimes 

 given to it. The Hop is another crop plant sometimes attacked by the 

 Gamma caterpillar. The moth may be found by day and night, in the 

 bright sunshine as well as in the dusk, and frequents all kinds of low- 

 growing plants. 



With us, except in 1879, the year when we shared in some degree 

 in the extraordinary and widespread infestation of this moth, which 

 spread from the north-west of Africa, across Europe to our own 

 southern shores, I believe that we have rarely suffered seriously from 

 this attack. The course and rate of advance of this most unusual 

 migration was duly recorded at the time, from its first observation in 

 the north of Africa in the neighbourhood of Algiers, about the 15th to 

 the 20th of April onwards, to its appearance via Strasburg, Paris, and 

 Ostend, on our own coasts, or in our southerly and easterly counties, 

 at dates from June 10th to 13th. 



