Mr. Frohawk, who had female butterflies living under observation for about three months, states that eggs were laid in April, May, and June. Caterpillars from the first batch of 192 eggs hatched early in May, nineteen days after they were laid. These were full grown by June 20, and entered the chrysalis state soon after. The butterflies from these commenced to emerge about the middle of July.
He says: "Both sallow and willow are equally suitable food for the larvæ, and birch is readily eaten, even when willow has formed the sole food until the last stage; they will feed on elm. Nettle was not appreciated, and not touched by them during the last two or three stages."
This butterfly appears to have first attracted the attention of the earlier British entomologists about the middle of the eighteenth century. Stephens, writing in 1827, remarks that "about sixty years since it appeared in such prodigious numbers throughout the kingdom, that the entomologists of that day gave it the appellation of the Grand Surprise." Harris figured the butterfly under the name mentioned by Stephens, and it has also been referred to by others as the "Willow Beauty" and the "White Petticoat." Newman called it the "White-bordered;" and from this, as well as from his description of the butterfly, it would seem that he had not seen any specimen, caught in Britain, with ochreous borders. Such specimens have most certainly been captured in these islands, and occasionally in some numbers, as, for example, in the autumns of 1872 and 1880. In the former year the butterflies were seen or taken in a great many parts of the kingdom. The single specimens that are taken now and then in the spring have hibernated, and possibly they may have just come over from the Continent. It is, however, equally possible that they may have arrived in the country the previous autumn and passed the winter here. After the invasion in the autumn of 1872, specimens were observed in January, March, and April, 1873, at places widely apart. In 1881 single specimens were taken in April in Surrey, Kent, and Brecknockshire; and in Essex and at Hampstead in August. One or two specimens were taken in the summer or autumn of the years 1884 to 1887 inclusive. In 1888 two were captured in Essex in May; and in August, three in Kent, one each Surrey, Hants, and Isle of Wight; and one in Kent in September. In 1889 a specimen was taken in Surrey in April, one in Kent, and one in Cambs in May; a few also in the autumn of that year. In 1891 a specimen was seen at Balham in September. In 1893 one was taken in Epping Forest in April, and one in South Devon in August. Single specimens were noted in Oxfordshire, Lincolnshire, Berwick, and the Isle of Skye, in September, 1896, and one at Epsom in December of that year. In 1897 one was recorded from Yorks (August), and one from Norfolk (September); and in May, 1898, one was taken at Norwich. One or two were observed in August or September, 1898 and 1899; and in 1900 there seems to have been an invasion, on a small scale, of this butterfly in August into some of the eastern and southern counties of England. It extended westward to Somersetshire, and northward to Roxburghshire. A few were taken in various southern localities, including south-east and north London, in August and September of 1901. A specimen occurred in the Isle of Wight in September, 1903, and one in September, 1904; and in the latter year one was captured in August at Raynes Park in Surrey. In 1905 one butterfly was taken at Harrow, Middlesex, on July 27; one at Norwich on August 26, and one in Suffolk on September 29.
Pl. 42.
Camberwell Beauty.
Egg enlarged; caterpillar and chrysalis.