Mellinus arvensis

LIST FROM COLLECTION OF C. MORLEY

121

Genus: DITRICHA. Sp. : *D. luttularis, Mg.—Breck, lOth August, 1928 ; 18th Sept., 1915, Tuddenham; 9th, lOth August, 1928, Mildenhall; 26th August, 1906, 9th August, 1928, Eriswell, Breck ; 26th June, 1918, Brandon ; 26th July, 1934, Andover, Hants ; 5th July, 1933, Polden Hill, Somerset; 23rd June, 1934, N. Forest.

(23 genera, 51 species, 34 in Suffolk).

ALASDAIR ASTON,

2nd June, 1953.

FURTHER OBSERVATIONS ON THE LIFE AND HABITS OF THE FIELD DIGGER WASP. Mellinus arvensis, Linn.

I did not observe so many variously colour-marked males and females this year, 1952. Mostly they were true to form, but they were much more varied in size. Here are some measurements : Males, 8-mm., 10-mm., 11-mm., 12-mm.

Females, 15-mm., 11-mm., 9-mm.

The normal or average male and female measure 9-mm. and 12-mm. respectively.

The lives of males were of shorter duration this year, lasting from the 5th August until the 27th August. None were observed after this date.

On three occasions this year, 1952, I found females feeding upon the heads of their paralysed prey, and so engrossed were they in this orgy, I was able to pick them up and hold them in the palm of my hand, separating them only by force. This probably accounts for other flies found abandoned outside nest holes minus their heads, but this does not account for those found minus their proboscides. See Transactions S.N.S., 1951, vol. VIII part III, page 102.

The common wasp, Vespa vulgaris, L., on occasions during August visited the nest site with the sole purpose of collecting these abandoned flies, which they did, biting off their wings and bearing them away.

122

FURTHER OBSERVATIONS ON THE DIGGER WASP

This year I unearthed an almost fully-fed larva : the following is its description—head and neck white, which when touched reacted telescopically, the mandibles black and strong, opening and shutting like pincers, abdomen dark red. When unearthed it was feeding upon the abdomen of afly,Calliphora vomitoria, the head and thorax were as yet untouched.

Below is a list of the Diptera and the places at which I have taken them from the wasps during the summers of 1950-51-52.

There are twelve different species in the lists.

At a man-made sand- Calliphora vomitoria L. hill, Bury St. Edmunds, Lucilia sericata Mg. situated in centre of Musca domestica L. 1950 town.

Calliphora erythrocephala Mg. Scaeva pyrastri L. Scatophaga stercoravia L. do.

Calliphora vomitoria L. Calliphora erythrocephala Mg. Musca domestica L. 1951 Lucilia sericata Mg. Syrphus Inniger Mg. Syrphus balteatus Deg.

do.

Calliphora erythrocephala Mg. Calliphora vomitoria L. Lucilia sericata Mg. Musca domestica L. J-1952 Syrphus balteatus Deg. Syrphus luniger Mg. Catabomba pyrastri L.

1 Disused gravel pit, Bury Lucilia sericata Mg. L1950-51-52 St. Edmunds. Outskirts Calliphora vomitoria L. of town.

Pollinia rudis F. Lucilia caesar L. 1950-51-52 Calliphora vomitoria L. Heiina lucorum Fln. As will be seen by the foregoing list, the Diptera preyed upon by this species of wasp varies in accordance with the numbers and species available in the localities where nests are situated.

On two occasions I have watched a wasp stalk and attack a species of the large grey-fleshfliesScarophaga, without success.

West Stow Heath, Breckland

FURTHER OBSERVATIONS ON THE DIGGER

WASP

123

T h e s e flies appear too strong for the wasp to hold. On both occasions they came face to face and as the wasp Struck, so the fly rose, knocking it completely off its balance.

I have watched and followed the habits of this wasp for the past three years and in that time I have found no parasites.

I have taken the fly Heiina lucorum Fln. on five occasions this year, 1952, in the vicinity of the man-made sandhill. It is odd that I have never taken it from a wasp or found any stored in the cells which I have unearthed at this place. From this it would appear that this fly is only hunted when other more favoured species are not available in large numbers, as such is the case on West Stow Heath.

HENRY

J.

BOREHAM,

November, 1952.

FOOTNOTE.—The Fly, Heiina lucorum Fln. at West Stow Heath, was identified by M r . L. Parmenter, who says that it does not appear to be recorded in Morley and Atmore's Suffolk L i s t ; it has once before been recorded as the prey of this species of Mellinus in H a m m & Richard's Paper -on the Biology of the Crabros—they were quoting an Observation made

by M r . G . M . Spooner. M y thanks are due to M r . S. Beaufoy for his interest in the identification and correspondence about this fly.—H.J.B.

SUFFOLK

BUTTERFLIES.

WE are indebted to Mr. E. T . Goldsmith of Beccles, for bringing to our notice the following article on Suffolk butterflies, written by the late Hon. Secretary and published in the " East Anglian Daily T i m e s , " of 14th August, 1920. It is thought that comment on this, in the light of any changes that may have occurred in the last thirty-three years, would be interesting. " East Anglian Daily Times," 14.8.20.

SUFFOLK

BUTTERFLIES.

" These be the pretty genii of the flowers, Daintily fed with honey and pure dew."

—HOOD.

There is no doubt that butterflies are dying out in this county.

I do not mean that there will ever be no butterflies here, but that the ones you see will be merely the common kinds—the Whites and Browns and Blues, the plebs of the highways and hedges.