532 
BIONOMIC NOTES 
though I cannot remember having made any mistakes of dia¬ 
gnosis myself. The mimicry is sufficiently close to have deceived 
for the moment such an experienced hymenopterist as Dr. H. 
Swale. 
Mortehoe, Devon, 1909. Of the Syrphid fly, Volucella bombylans, 
Linn., both forms occur, plumata and bombylans ; they are close 
mimics of Bombus terrestris and Bombus lapidarius respectively, 
and I have actually taken the latter form of the fly for the 
Bumble-bee. 
Mortehoe, Devon, 1909. The Syrphid fly, Ardopkila mussitans, 
Eabr., is so extraordinarily like the tawny Bumble-bee, Bombus 
agrorum, on the wing that I have several times been thoroughly 
deceived. I have taken the two insects together, on the same 
day, on the same patch of Centaurea nigra; the Bumble-bee 
very common, the fly comparatively scarce—all the classical 
conditions of Batesian mimicry. 
New South Wales, 1910. I do not think that I have ever been so 
completely taken in as at Como, near Sydney, on the 2nd of 
April. On the flower of a shrubby Acacia, well within reach 
and clear sight, was, as I thought, a fine wasp. It was easily 
netted, but not so easily bottled. I pursued it up and down the 
net with cyanide-bottle, taking great care not to be stung. Once 
corked up I thought no more about it, until on turning out the 
bottle after the day’s work I found a black and orange Longicorn 
beetle! The female of Bsthesis variegatus, Fabr., has extremely 
short elytra, and as the beetle sat on the flower its wings were 
extended on either side, as one often sees in Fossors (see 
Plate VI., Figs. 8, 9). I did not observe any wasp very like it 
(but see above, p. 485). 
Mortehoe, 1907, and subsequently. My garden is unusually rich in 
Diptera mimics, though the number of individuals is mostly 
small. This is true of the enormous black Tachinid fly Bchi- 
nomyia grossa, Linn., which in appearance, voice and manner is 
a good mimic of Bombus hortorum, var. harrisellus. As neither 
is common, I have not seen them together, though I have taken 
them within a few yards of one another. That they can be 
distinguished on the wing is doubtless true, but I venture to 
think that it is also possible to confound them. 
Of course we can form but a very imperfect idea of the sense 
impressions of the lower animals. We know by their actions that 
hawks see their prey from a considerable distance. The phenomena 
