The Chalkhill Blue

TRANSACTIONS T H E CHALKHILL BLUE (Lysandra coridon Poda) OVIPOSITION.—A few years ago a number of females of the Chalkhill Blue were captured with the object of obtaining ova and of rearing the insect through all its stages. T h e butterflies were collected in Somerset and taken to Devon, where I was staying at the time. T h e usual food-plant of the larvae, the Horseshoe Vetch (Hippocrepis comosa), was not available, so the females were enclosed on Bird's-foot Trefoil (Lotus corniculatus), which is stated to be an alternative food-plant. N o ova at all resulted.

T h e following year females were enclosed with Horseshoe Vetch, and many ova were obtained, either upon the stems or leaves of the plant itself, or upon stems of grass or other plants growing among the Vetch.

This year, 1954, I obtained five females at Newmarket and enclosed them in rotation under netting over five flower pots, No. 1 containing Horseshoe Vetch ; No. 2 Birdsfoot Trefoil with chalk soil (I thought that possibly the nature of the soil might influence oviposition); No. 3, Birdsfoot Trefoil with a neutral soil ; No. 4, Kidney Vetch (Anthyllis vulneraria) ; and No. 5, various grasses. All the butterflies laid eggs in pot No. 1, except one which escaped before it was admitted to this pot, and none laid eggs in any of the other pots.

T h i s was only a small-scale experiment and needs to be repeated on a m u c h larger scale, but it would appear in general that the presence of Horseshoe Vetch is usually necessary for oviposition.

FOOD-PLANT OF L A R V A E . — A few years ago, larvae hatching from ova in the spring were first placed on Birdsfoot Trefoil, as Horseshoe Vetch was not apparently available near Ipswich.

(I have since found a small patch of this latter plant by a chalk pit in East Suffolk.) T h e larvae refused to eat this, and neither would they touch Kidney Vetch, and eventually they all died.

T h e following year the newly-hatched larvae were placed on Horseshoe Vetch, and there was no trouble at all in rearing them through to the final butterflies in August. Here again more experiments are required, but it is possible that, in this country at least, Horseshoe Vetch is the only food-plant of the larvae.

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THE CHALKHII.L BLUE

' RECORDS OF FOOD-PLANTS.—Tutt in his exhaustive treatise on this species (Tutt, 1910-14) gives a large number of food-plants, but it should be noted that most of his records are of Continental origin, and it is possible that the habits of the European L. coridon are different from those of the British insects. Tutt states that on the continent the two vetches Coronilla varia and Astragalus glycyphyllus are common food-plants of the species. These two plants are local and scattered in this country, but it would be interesting to experiment with British insects on these plants ; in a similar way it would be instructive to try Continental insects with the common British Birdsfoot Trefoil and Kidney Vetch.

Other SufFolk Naturalists might like to carry out further experiments in the years to come. The butterflies are not now found in Suffolk, unless possibly on the chalk near the Cambridgeshire border, but they are quite common along the Devil's Ditch at Newmarket.

BIBLIOGRAPHY.

Tutt, J. W. (1910-14).

British Butterflies, vol. IV. London : Stock.

Stokoe, W. J. (1944).

The Caterpilars of the British Butterflies. London: Warne.

Allan, P. B. M. (1949). Larval Food-plants.

London: Watkins and Doncaster.

Frohawk, F. W. (1934). The Complete Book of British Butterflies. London : Ward Lock.

S. BEAUFOY.

NOTES ON REARING LEPIDOPTERA, 1954 PURPLE EMPEROR (Apatura

iris Linn.).—Of the six larvae which hatched in August, 1953, from ova found in Suffolk (vol viii, p. 130), five entered into hibernation on the same Sallow sapling as had been used for a similar purpose during the previous winter. Of thesefive,two died in the spring of 1954, and the others produced males in July. These butterflies were released in the wood in which the ova had been found. No other Purple Emperors were seen by me in this wood this summer (the weather did not allow many visits), but they are still there, as after a short search I found one egg on the same bush where a few had been found the previous year. This egg was brought home, and the resulting larva is, at the time of writing (22.9.54), about to enter its third instar.