JQ4 ' I October, 



NOTES ON THE LIFE-HISTOEY OF THE SECOND BEOOD OP 

 PL A TTPTIL1A G ONODA CTYLA. 



BY J. W. TTTTT, P.E.S. 



The fact of Platyptilia gonodactyla being double-brooded has been 

 known to individual Lepidopterists for some years, but up to the 

 present time it has been unknown how the larva? of the summer brood 

 fed up. It is a well-known fact that the larva? of the June brood 

 feed in the capitula of Tussilago farfara, but since the plant only 

 blossoms in early spring, it was impossible that the second brood 

 should feed in the same manner. Mr. Gregson once bred a moth 

 (Entom., vi, p. 427) from a larva feeding on the under-side of T. 

 farfara, and (Entom., xviii, p. 151) suggested this might be the con- 

 tinental farfarella, Zell. I pointed out at the time (Entom., xviii, 

 p. 170) that it was more than probable that this was simply a speci- 

 men of the second brood of gonodactyla, and that the way it had fed 

 would prove to be the ordinary way of feeding of the autumn brood 

 of gonodactyla. This supposition I have fully confirmed during the 

 present summer. 



In May my little son collected a large quantity of the flower- 

 heads of T. farfara, and I bred a large number of specimens of 

 gonodactyla during June. Towards the end of that month it struck 

 me that I could easily find out how the second brood fed up, and 

 potting up a plant of T. farfara, I enclosed six pairs of newly 

 emerged gonodactyla. During the following week a large number of 

 ova were laid ; the larva? hatched on July 2nd — 5th, and changed to 

 pupa? on August 25th — 27th. 



The following notes may be of use : — 



The ova are somewhat ovate in shape, and laid upon the long edge, not on the 

 apex ; tho colour pale pea-green, and apparently smooth ; chiefly laid deeply among 

 the fluff on the under-side of the leaves or on the stem, but some were laid on the 

 muslin or on the flower-pot. (Those that were laid on the muslin had been often 

 pushed through the tiny holes and deposited on the outside.) 



First appearance of larva on July 2nd and 3rd, when numerous tiny mines 

 were noticed in the under-surface of the leaves. On July 7th, a thorough examina- 

 tion showed a number of small round holes in under epidermis, and mines leading 

 from these ; the larvae in the mines were most inconspicuous, and could only be 

 traced by their black heads. 



On July 10th, I found a large number of tiny larvre — pale green, with black 

 heads, the two following segments with a black plate and a dark dorsal streak — 

 mining under the fluff both of leaves and stems. The larvse were now conspicuous 

 enough, many wandering about on the outside of the under-surface of the leaves. 



