43 



NOTES AND OBSERVATIONS. 



Notes on Variation in Malacosoma (Bombyx) neustria. — Ou the 

 30th May I found a nest of the larvre of ^[. neustria, about half grown, 

 feeding on wild plum. Wishing to discover whether different food- 

 plants had any part in causing the considerable variations in the 

 imago, I divided the larvfe roughly into two batches — giving one 

 ordinary garden plum, and the other apple. In due course about 

 thirty-five pupated, and the moths began to emerge on July 22nd — 

 ten females and one male on that day, and three females and four males 

 on the 23rd. Twelve more, all males, emerged up to August 4th. It 

 will therefore be noted that the bulk of the females emerged first. Of 

 course, a much longer series of experiments would be necessary before 

 arriving at any definite conclusion ; but it may be interesting to put 

 some of the facts ou record, as a starting-point for further investi- 

 gations. I must here acknowledge my indebtedness to Mr. P. A. 

 Oldaker, of Dorking, for some interesting notes with respect to larvte 

 fed on apple and blackthorn, which notes I have incorporated. In the 

 first place, there was a much greater disparity between the numbers of 

 the sexes in those fed on apple and blackthorn than in those fed on 

 plum, viz. on apple — (Dorset) three females, eight males ; (Surrey) 

 seven females, eleven males; or a total of ten females to nineteen 

 males. On blackthorn — (Isle of Wight) two females, eight males ; 

 while on plum (Dorset), ten females to nine males. In colour there 

 was nothing sufficiently distinctive of either batch to be noted ; but 

 there was an abrupt line of demarcation between the brown and yellow 

 males — the brown, though varying in intensity, being always brown, 

 never approaching yellow ; the yellow constant in tone. As to number 

 — Mr, Oldaker was not fortunate enough to get any yellow males either 

 from the apple or blackthorn ; but of mine, the apple produced six 

 yellow and two brown ; the plum, four yellow and five brown. The 

 sizes across the wing when set were — Apple : Dorset, females 38- 

 39 mm., males 29-30 mm. ; Surrey, females 36^ mm., males 28 mm. 

 Plum: Dorset, females 37-38 mm., males 29-30 mm. Blackthorn: 

 Isle of Wight, females 32 mm., males 28 mm. — James Douglas; 

 Sherborne, Dorset. 



AciDALiA degeneraria PARTLY DOUBLE -BROODED. — Last year (1902) 

 I took, at Portland, a few worn A. degeneraria, and, contrary to my 

 expectations, obtained some ova from them, which duly hatched. The 

 larvae fed up satisfactorily, and the perfect insect commenced emerging 

 on June 2nd last. On the 7th a pair mated, and ova were deposited on 

 the 12th. Two other pairs were mated on the 22nd and 23rd, and 

 eggs were laid on the 25th and 26th. On the 25th the first batch of 

 ova hatched ; and on July 1st the other two lots, which had been put 

 into one box, commenced hatching. All the larvfe were subsequently 

 put together. Towards the end of July I noticed that six of the larvie 

 were much larger than the others, and on Aug. lOtli one of them spun 

 up. On the 15th another had spun, on the 20th two more, and I 

 found two that had pupated without spinning any w'eb, one of which 

 was deformed. On Sept. 2nd a pair of perfect insects emerged, and 

 I found them mated on the night of the 3rd. Eggs were laid on the 



