OF THE ANTENNÆ OF INSECTS. | 393 
them. In the interior of the antennæ, underlying the organs, is found a lobulated 
membranaceous mass (fig. 2 b), in which the extremities of the nerve lose themselves. 
It is difficult to make out the precise structure of the mass; but it seems composed of 
a number of membranous sacculi. It occurs in a great number of insects, and princi- 
pally, if not always, in those whose organs are not dilated into a distinct sac in the 
antenna-wall. 
In Pygera bucephala I have noticed a depression om each segment of the antenna, 
similar to those observed in some Coleoptera. 
.. ln the Ghost Moth (Hepialus humuli) the organs are in appearance more like those of 
the simple sort in the Diptera, and are dispersed over the whole antenna. The male and 
female antennæ and antennal organs are precisely alike; and it may be stated, as a rule, 
that those Moths which possess such an exquisite sense of smell as Orgyria antiqua have 
the organs more developed in the male than in the female, but they do not seem to be 
more numerous than in those Moths which are reputed to possess a more obtuse olfactory 
power. 
In Anthocera loti (Burnet Moth) the organs may be easily detected, being very 
distinctly placed in a slight depression between the cuticular projections covering that 
part of the antenna in which they are situated. The closing-in membrane is irregularly 
circular, of a diameter of 445,5 inch, and has a small papilla in its centre (S. fig. 1 #, 
fig. 2 b). Behind this is a bowl-shaped sac, which has projecting into it a small papilla 
in the centre of its inner wall, probably where the nerve impinges. This is shown in 
the section at S. fig. 2 a, while at c the hair-like cuticular projections are seen partly over- 
hanging it. : : 
The antenna of Macroglossa stellatorum is peculiar in having one side of each segment 
furnished with numerous rows of hairs. In the centre of each facet may be seen sacs 
(fig. 194). These hairs give a peculiar appearance to the antenna. They gradually 
enlarge towards the exterior of each facet, and possess large roots or follicles. 
In Sphinæ ligustri (Privet Hawkmoth), the organs are to be found from base to apex 
Pheng ligustri (Priv å ede | bou 
on every segment, on one side only, and in considerable profusion ; and, so far as 
‚make out, are on the same plan as in the Burnet Moth. 
I have examined many specimens of foreign species of 
organs are on precisely the same plan, and as numerous, 
my former paper. | | ig). F 
| | : : g) Fourteen 
At U, I have drawn the antenna of Forficula auricularis en — me res 
segments are found to possess the sacs ; from one to — - 9 a: their diameter at 
end, as in fig. 1 aaa. Their shape may be seen : section at fig. å 4; 
the surface is about 5455 inch | 
2300 . bout three or 
I have also examined the antennæ of an Agrion å they as in Libellula, 
four) of the simple cells I mentioned as occurring in Suc be d but a very rudimentary 
While in the common May-fly (Ephemera diurna) they exist m 
condition, | | tV 
: uc s, as shown at V., 
In the parasites also, the antennæ are furnished with similar organ 3F 
VOL. XXII. 
Tetrix of all sizes, and find the 
as in the Zetrix described in 
