The Aculeate Hymenoptera of the British Isles. 



By G. E. Frisby, F.E.S.—Read Octoher 2Qth, 1920. 



The Aculeata, or stinging Hymenoptera, consist of four main 

 divisions : — The Ants ; the Fossorial Hymenoptera, which include 

 the many species popularly known as Sand Wasps and Wood 

 Wasps ; the true Wasps ; and the Bees. Many authorities also 

 include the Chrysids, or Firetails. With the Chrysids, however, 

 and the Ants, I shall have nothing to do to-night, but shall confine 

 myself to the three other divisions. I am not qualified to give a 

 descriptive account of each British species, though there are com- 

 paratively few that I have not met with, but I think that some 

 remarks on the habits, distribution, and occurrence of a number of 

 them will perhaps be of interest. 



Taking them in their usual order of arrangement, we will first 

 speak of the Fossorial group, many of which our American cousins 

 call " Huntress Wasps." The greater number of these construct 

 burrows in wood, sandy banks, bramble stems, etc., in which they 

 make their cells and then provide a store of sustenance for their 

 larvae by capturing other insects, or m some cases spiders, which 

 are either paralysed by stinging, or killed outright. These are then 

 placed in the cell provided, and an egg placed on the body. In 

 this the females only are engaged, which accounts for the name of 

 " Huntress " Wasps. The first family, the Midillidae, appears to 

 be parasitic, the largest British species, Mutilla enropaea, having 

 been found fairly often in the nests of Humble Bees, though it 

 has also been dug out of a sandy bank from amongst a quantity 

 of wings of Diptera. It is not a very common insect, though it 

 apparently occurs over the whole of our southern counties, as do 

 the rest of the family. I have only met with it on the sandy hills 

 near Rye Harbour, where it can sometimes be found endeavouring 

 to climb up the loose sand in hot weather, or induced to show 

 itself by agitating the tufts of marram grass above the sandy 

 slopes. The winged male occurs occasionally on bramble flowers. 

 The closely allied Mutilla rK/i/iea is smaller, and very much more 

 abundant, being found in most sandy localities. I have found it 

 in considerable numbers on the clift's at Sandown Bay, in the Isle 

 of Wight, running up and down where a large colony of the bee 

 ColU'ti's (lavifmna occurred. It occasionally entered the burrows of 

 the bee, but as it seems to search every crevice it meets with, I could 

 not say that there was any connection between it and the bee. The 



