Life and Habits of Silver Spring Digger Wasps

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LIFE AND HABITS OF COMMON DIGGER WASP

All the nests under Observation were in positions that received the fĂźll rays of the sun at its hottest. When these were cut off by clouds, the hunting activities ceased until they reappeared.

Specimens of the diptera mentioned were identified by our member Dr. C. D. Day. One specimen was taken on West Stow Heath, 31st July, 1955.

H E N R Y J. BOREHAM.

SOME OBSERVATIONS ON THE LIFE AND HABITS OF THE SILYER SPRING DIGGER WASP Oxybelus argentatus Curt.

I have occasionally observed the solitary females of this species on West Stow Heath, Breckland. Two in July, 1952, and four in July, 1955, usually on those parts which have little Vegetation.

These are probably the first records of its presence in Suffolk.

Of two nests under Observation one was situated on the flat sandy surface and the other in the side of a shallow hole, and were five and six feet respectively from the surrounding edge of the densely growing sand sedge, Carex arenaria, amongst which the prey was hunted.

T h e prey was paralysed, on two occasions not perfectly so.

It was observed that when being taken into the nest, the impaled fly was moving its abdomen rhythmically up and down. When being transported to the nest it was held rigid impaled upon the sting, which was inserted in the centre of the underside of the thorax, the insect always lying over to the right, head foremost and touching the wasp's abdomen.

Four specimens of the dipterous prey were taken from the nests, one in July, 1952 and three in July, 1955 and all were of the same species Thereva plebeia Linn.

T h e wasp which had its nest on the flat caught and transported five flies over the same route at various intervals during a period of 35 minutes, crawling down the leaf blades of the Sand Sedge and running, with occasional pauses, a distance of five feet over the almost barren sand : the other transported its prey by flight.

T h e nests were sealed with sand which was removed each time on arrival with the prey, and replaced by the wasp when leaving, but remained open during the short period of storing it. When the wasp entered, she rapidly removed the sand by scraping it away with the forefeet, the abdomen and impaled prey being slightly raised to allow the sand to pass freely under the b o d y :

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on leaving she resealed the nest by scraping the sand with the forefeet, this passing under the body back towards the nest. No particular effort appeared to be made in doing this, and occasionally the task was left incomplete. A small ledge formed part of the entrance to the nest situated in the shallow hole ; upon this the vvasp alighted and carried out the foregoing work quite easily.

REMARKS : This species of Oxybelus is referred to by A. H. Hamm and O. W. Richards (Trans, Ent. Soc. Lond., 78 Part 1.

Pages 117 and 126, June 30th, 1930) in their paper on " T h e Biology of the British Fossorial W a s p s " as an inhabitant of the sandhills of the west coast of England and at Porthcawl, and its only prey appears to be the equally silvery fly Thereva annulata F. Occasionally a male and female of this silvery species T. annulata have been taken on West Stow Heath and on three occasions females were observed depositing ova in the hot sand, quite near the nests of O. argentatus which passed over them without regard.

Specimens of Thereva plebeia Linn were identified by Dr. C. D. Day.

HENRY J.

BOREHAM.

UNCOMMON FLORA OF SUFFOLK

By F. W .

SIMPSON

This article (continued from page 43) enumerates some of the more interesting plants of the County which have become rare or are now presumed extinct. There is a number of very doubtful Suffolk plants, and where no herbarium specimens have been traced it is probable that the old records are incorrect.

Inula crithmoides L.—Golden Samphire. A doubtful Suffolk plant of muddy salt marshes. No herbarium specimens.

It occurs, however, a few miles south of Felixstowe in Essex ; sparingly in the extensive marshes between Dovercourt and Walton, and there is the possibility that it may extend its ränge into Suffolk.

Pulicaria vulgaris Gaertn.—Small Fleabane. Very rare and probably extinct. Old records for Framlingham and Bramford. A plant of moist sandy heaths and places flooded during winter, decreasing species everywhere. Pulicaria dysenterica (L.) Berhn.—Fleabane—is very frequent all over the County in suitable moist and fairly open habitats. [ Antennaria dioica (L.) Gaertn.—Cat's-foot. Formerly on heaths at Cavenham, Culford and Newmarket. Almost certainly extinct in Suffolk and now gone from many localities in the south of Britain.