SOLITARY BEES AND WASPS OF ESSEX. 93
Willughbiella, K., nests in decaying trees (especially willows),
sometimes by thousands ; also in posts ; utilises rose and labur-
num leaves, and is partial to flowers of the Campanulaceae and
Compositae ; Billericay, Hale End, Colchester district, etc. ; one
of the commonest of the genus and sometimes known as the
willow bee. Circumcincta, K., nests in the ground ; local ; fond
of bird's-foot trefoil, but forms its cells of rose-leaf cuttings;
Billericay, Colchester district. Ligniseca, K., nests in dead
wood ; local ; prefers thistles and knapweeds for feeding
purposes and comes to wild geraniums in my garden, but uses
elm and other leaves for its cells ; Billericay, Hale End,
Colchester district. Centuncularis, L., probably the best known
species, as it prefers rose leaves for its cells and nests in wood ;
Billericay, Hale End, Colchester district, etc. Versicolor, Sm.,
nests in dead wood and uses rose leaves for its cells ; partial to
Lotus and Inula, Colchester district. Argentata, F., nests in the
ground, especially sandhills, and, like Maritima, essentially a
coast insect ; flight exceedingly rapid and hum shrill ; frequents
wild thyme, Lotus, Echium, etc. ; St. Osyth, Southend.
Caelioxys, Latr. Parasitic on Megachile, and all possess the
power of emitting an offensive odour, which probably protects
them against birds and other insect eaters. Rufescens, Lep.
(parasitic on M. circumcincta), local ; Colchester district.
Elongata, Lep. (on M. maritima and willughbiella), Billericay,
Colchester district. Acuminata, Nyl, (on M. centuncularis and
versicolor). Common ; Hale End, Colchester district, etc.
Anthidium, Fab. Utilises burrows formed by other insects
in dead wood and lines them with the tomentum scraped off
woolly plants such as Stachys sylvatica, Agrostemma coronaria (in
gardens), etc. ; cells enclosed in a membrane. Manicatum, L.
(Hoop-shaver Bee) ; male larger than the female—an unique
instance amongst British bees ; visits Geranium, Ballota nigra,
Lamium purpureum and other Labiates ; Billericay, Colchester
district, Hale End, etc. ; common.
Stelis, Panz. Parasitic on Osmia ; partial to the flowers of
mallows and yellow Compositae. Aterrima, Panz, (on O. ventralis);
Billericay, Colchester district. Phaeoptera, K. (on O. ventralis and
caerulescens)., Billericay, Hale End, Colchester district ; rare.
Osmia, Panz. A genus characterised by the diversity in
nesting habits of its species. They collect pollen on the under-