(9m) 
occasionally counted as one, but as it forms a component 
part of the scape, and does not articulate with it, it must be 
necessarily included with it as one. They vary in length 
in the sexes; they are generally filiform and slightly curved, 
sometimes much so (Mutilla, female, Tiphia, female, some 
of the Pompili, females, and Arpactus), rarely porrect (As- 
tata, male), and as rarely capitate (Sapyga prisma, 
male), often subclavate (Sapyga, Nysson, Mimesa, Try- 
poxylon clavicerum, Cerceris, Philanthus), distinctly geni- 
culated in Mutilla, Crabro, Pemphredon, &c.; the joints 
vary in shape, generally cylindrical, sometimes subarcuate 
(Methoca, male), in the males of some species of Vysson 
the apical joint, and in some Crabros the basal joints of the 
clavolet are emarginate, in some males of the latter also the 
entire clavolet is occasionally fringed with curled hairs, 
sometimes merely at its base, and in the latter case it is 
generally compressed (C. cribrarius, patellatus). They are 
usually inserted in the middle of the face, frequently very 
near the clypeus, sometimes upon a slight protuberance, 
often approximate but occasionally distant. Their uses 
have been so often sought, and so vainly hypothesis* has 
been heaped upon hypothesis, that my own conjectures it 
is fruitless to state. ‘They have been considered as organs 
together. Some further observations of mine upon this subject will be found 
below, in the descriptions of those male Crabros which have the basal joints 
of the clavolet emarginate. 
* Mr. Newman’s ingenious hypothesis of their fuller development at the ex- 
pense of the eyes in insects that fly by night, and the great development of the 
eyes and decrease of the antenna in those which fly in a bright light, is hap- 
pily conceived and illustrated in the instance of the Melolonthide, Syrphus and 
Libellula, but it is not supported by our insects, which are invariably lovers of 
the brightest sunshine, so much so, that if but a transitory cloud flit before the 
sun, they as suddenly disappear ; but still, except in one insect, the male of As- 
tata, they do not entirely contradict his theory, from the position of their eyes 
being lateral. 
