1891.] 317 



instead of a variety, as I now place it, it will be distinguishable from mimulina by 

 the following : — Triangular patch on upper-side of fore-wings smoky instead of 

 reddish, and enclosing on its lower edge a bright silvered dot in place of white one 

 of mimidina ; under-side of fore-wings sulphury -white instead of snow-white ; under- 

 side of hind-wings with a black discal spot, and a series of black dashes between the 

 nervules on the outer border at base of fringe ; the rest as in mimulina. 



Santiago, Chili : 1890. 



I 



LIFE-HISTORY OF PLUTELLA ANNULATELLA, CURT. 

 BY >-ELSO]Sr M. RICHARDSON, B.A , F.E.S. 



Since I have collected at Portland, I have been more or less on 

 the look-out for the larva o£ P. annulatelln, but have never come across 

 it until this year, though I have before seen traces of its presence. 



I first made acquaintance with this species by shaking an imago 

 out of an overhanging tuft of grass on September 27th, 18S7, and 

 this is the only clue that I have to its mode o£ hibernating, as my 

 other captures have all been made in June and July, in which months 

 I have taken a few each year, but not more than about 20 altogether. 



The plant on which it feeds {Cochlearia qfficinaUs) is common in 

 many parts of Portland, but the larva seems to be rather local, as in 

 some places it did not appear to be present, though there was plenty 

 of the food-plant ; where it occurred at all, it was not uncommon, 

 though until one knew something of its habits, one might easily pass 

 it by unnoticed. 



The egg is apparently laid in the flower-bud, as the young larva, 

 which could not in some cases have been hatched more than a day or 

 two before I found it, draws together the petals slightly with silk, and 

 lives inside them, ejecting its frass through the small gaps in its 

 habitation between the petals. It was in this state when I first dis- 

 covered it in the middle of May, all the larvae at that time being rather 

 small. As the larva grows, it gets too big for its first little house, not 

 to mention the fact that it has eaten its contents, and for the rest of 

 its larval life it spins a few threads of silk amongst the bunch of 

 flowers and seed pods in a flower-head, and eats flowers, seeds, pods, 

 leaves, and stalks, preferring them in the order in which I have named 

 them. The extent to which a large larva can conceal itself in a flower- 

 head, which seems quite open to observation throughout, is most 

 extraordinary. I have sometimes thought that one might be present 

 from seeing a little eating or a thread or two of silk but could not see 

 the larva itself until I ])inched the seed-head, when it iiiiiiiediately 



