Some Further Observations on the Habits of the Field Digger Wasp

I^Z

LEPIDOPTERA IN SUFFOLK

a similar number of the Pine Beauty (Panolis flammea, Schiff.), the White Colon (Heliophobus albicolon, Hübn.) the Orange Footman (Eilema sororculs, Hufn.), the Maiden's Blush (Cosymbia punctaria, Linn.), the Water Carpet (Lamprotteryx suffumata, Schiff.), the Grey Pug (Eupithecia castigata, Hübn.), the Mottled Pug (E. exiguata, Hübn.), and the Narrow-winged Pug (E. nanata, Hübfi.), while the Grey Pine Carpet (Thera obeliscata. Hübn.) and the Bordered White (Bupa/us piniaria, Linn.) were locally abundant. The only capture of note at Southwold was the Lime Hawk (Mimas tiliae, Linn.) on 21st June.

SOME

THE

FURTHER

FIELD

OBSERVATIONS

DIGGER

WASP

ON

THE

(MELLINUS

HABITS

OF

ARVEN

SIS,

LINN.) by

HENRY J. BOREHAM

HABITAT

FOÜR females of this solitary species were observed on 27th August, 1961, working in a bank by the footpath which forms the boundary between two gardens at Cornfield Road, Bury St. Edmunds. The habitat, facing north, is sheltered from the moisture-bearing air which usually comes from the west-southwest ; it receives füll sunlight for most of the day. T h e soil is a mixture of earth and chalk ; it is bare of Vegetation and is frequently trodden and wheeled upon : in consequence it remains hard and solid throughout the year.

T H E PREY

Lach wasp upon arrival at its respective nest hole was occasionally robbed of its prey ; this varied considerably, as will be seen by the following list of the species of flies together with the numbers taken.

Pollenia rudis, Fab. 4 Calliphora vomitoria, Linn.

2 Lucilia caesar, Linn.

1 Dexiosoma caninum, Fab. 1 Lonchaea chorea, Fab. 2 Lonchaea flavidipennis, Zett.

1 Metasyrphus luniger, Meigen 1

FIFLD

DIGGER

WASP

AND P R E Y

Photograph by S.

Beaufoy

X

4

FIELD DIGGER

W A S P AND PREY

Photograph by S.

Beaufoy

X

16

THE FIELD DIGGER WASP

193

It was interesting to observe that the two species of Lonchaeidae were the smallest species of flies, 5 and 6 mm. in length which 1 have taken from M. arvensis. This female M. arvensis was also smaller than usual and measured 10 mm. in length. The entrance hole of her nest was also smaller than the average, and measured only 5 mm. across. The length of life of the recovered paralysed flies averaged four days.

REMARKS

A. H. Hamm and O. W. Richards in their paper " The Biology of the British Fossorial Wasps "* illustrate on page 97 six females of M. arvensis, photographed after death, still gripping their prey by the proboscis. Nothing is stated as to how these specimens met their death or how likely they were to remain in this attitude.

I have a specimen in just such an attitude ; it is gripping the Blow Fly Calliphora vomitoria by the proboscis. Its death was caused by a stinging blow from a stick while it was in flight. The sudden impact probably produced a stimulus on the sensory nerves from which they were unable to relax at death. The blow caused a Splitting of the mesonotum at and over the joining of one wing ; no other outward injury could be seen.

From a long experience of observing the habits of M. arvensis I have found that many of them, after having been smitten down two or more times with the open hand, were reluctant to release their grip upon the prey ; this was strongly marked on the days when a cold breeze was blowing. When cold weather is continuous, death usually comes before the work to ensure the future of the species is completed, and through the tenacious habits of M. arvensis it is possible that some may die in the attitude described.

BIBLIOGRAPHY

* H a m m and Richards.

T r a n s . R. E n t . Soc. L o n d . 30th June, 1930.

Boreham, H . J. (1953). T h e W h i t e - m o u t h e d D i g g e r W a s p Coelocrabro leucostomus L i n n . S o m e observations on t h e L i f e and Habits. T r a n s .

Suffolk N a t . Soc. 8, 181.

MOVEMENT

OF by

WHITE

BUTTERFLIES

S . BEAUFOY

THERE are several indications that in Great Britain in the Spring a northerly movement of Whites takes place (Large White, Pieris brassicae, L. ; Small White, P. rapae, L. ; Green-veined White, -P. napi, L.) ; while a southerly movement can be observed in late Autumn.