August, 18S2.] 49 



THE NATURAL HISTORY OF RIVULA SERICEALIS. 

 BY WILLIAM BUCKLER. 



Herein I have to give the history of this species from the egg, 

 and to show how, after the first failure to solve the problem of its 

 food-plant, a second trial ultimately proved successful, and for this I 

 have to acknowledge my indebtedness to Mr. W. E. Jeffrey, for his 

 kindness in enabling me to work it out most thoroughly, ox which 

 indeed the full-grown larva and pupa were evidently known to Guenee, 

 but the food plant had not been observed ; probably, the larva had 

 been captured after ceasing to feed, and so gave no clue to its food ; 

 but we now know for certain the food of its own choice. 



The first attempt was made in 1878 from eggs which Mr. Jeffrey 

 induced a captured female moth to lay upon leaves of various low 

 plants, from 12th to 11th of July, and in the share he kindly sent to 

 me I found two eggs on a bramble leaf, four on Stachys syJvatica, one 

 on SoJidago virgaurea, and one on Fragnria vesca : they all hatched on 

 the night of the 20th, and the young larvae were provided at once with 

 leaves of all the above-named plants, besides others, and next day, on 

 seeing none were eaten, other kinds of leaves were given in turn, but 

 the tiny creatures refused every kind of nourishment offered them, 

 and died of starvation, and those with Mr. Jeffrey shared the same 

 fate. 



In 1881 Mr. Jeffrey was able to obtain another batch of eggs 

 from sericealis, and he again gratified me witli part of them on the 

 24th of July, laid on Lotus major, a plant he had observed to be plen- 

 tiful where the parent moth was captured, though she laid one cluster 

 of eggs without attachment to any plant ; in the evening of the 29th, I 

 found a single larva hatched, and twenty-four more next day, when all 

 were put on the LoUis, and some other different leaves were tried both 

 by Mr. Jeffrey and myself, with increasing anxiety at finding nothing 

 eaten, and the larvae, one at a time, were beginning to die off in evening 

 of 31st, when the last thing I happened to put with them was a piece 

 of the leaf of Phalaris arundinacea ; next morning I was greatly re- 

 joiced to see this bit of coarse grass, when held against the light, 

 showing a number of transparent lines of varying lengths, and the 

 fact was immediately communicated to Mr. Jeffrey, and afforded him 

 a clue to the proper food-plant, as he confidently assured me no fha- 

 laris grew where the parent moth was taken, and therefore could only 

 be a substitute food ; in this belief, he accordingly took pains to clear 

 up the point by again visiting the locality, while my eleve'n surviving 

 larvse were growing, and presently moulting from 8th to 12th August. 



