ORGANS FOUND ON THE HALTERES AND WINGS OF INSECTS. 143 
In Lucanus Cervus, Melolontha vulgaris, and Cetonia aurata they are not so large, but 
still are numerous. i 
In Carabus granulatus they are found in the rudimentary second wing, more diffused 
over it than in some other genera, inasmuch as other nervures than the subcostal are 
furnished with them, though not to the same extent. 
In an apterous Beetle which I examined, I did not find any similar organs on the part 
of the side corresponding to the position of the wings. 
With regard to the distribution of the nerve in the elytron of the Coleoptera, there are 
some curious facts, which, I think, have not been hitherto noticed. If the elytron be 
treated in the way above mentioned, and first bleached if it be dark-coloured, the 
branching tracheæ will at once be recognized, accompanied by the nerve, which gives 
out branches as it proceeds. Now, in all the elytra of beetles I have examined, there is a 
number of distinct projections from the whole dorsal surface, in many hemispherical, in 
some like small papillæ just raised above the cuticular surface; these eminences are 
arranged in a tolerably regular manner, and are quite distinct from other irregularities of 
surface. The hemispherical forms are very transparent, the wall of the elytron being 
deficient beneath them, as in those before described. There are two or three papillæ at 
the highest point of the vesicle. Some, when viewed by polarized light, exhibit a dark 
cross, something after the manner of starch-cells; those of Melolontha show it well. 
In many beetles the vesicle or papilla is accompanied by a hair, which always, I 
believe, when so situated, overarches it, as if for the purpose of affording protection. 
Now, into each of these vesicles and papillæ a branch of the nerve can be distinctly 
traced, as I have shown in the two drawings taken from Melolontha (Tab. XXVII. fig. 2) 
and Carabus (Tab. XXVIII. fig. 1). In the case of Melolontha the hair may be seen 
overarching the vesicle. ; 
With regard to the Lepidoptera I have found nothing new, except that the organs 
are well developed in the female Vapourer Moth (Orgyia) on the rudimentary wing. 
In none of the Orthopterous specimens hitherto examined have I been able to find 
any structure like that described in the other groups. Å nerve, small in some, but large 
in Mantis religiosa, is to be found entering the wings, yet I have been unable to make 
out anything satisfactory, except a few scattered vesicles on one or two of the nervures. 
~ In the Neuroptera these organs can be distinctly found, though not quite so fully 
developed as in most of the preceding groups. In Libellula depressa they are not, rela- 
tively to the size of the insect, by any means so numerous as in the Coleoptera. I have 
drawn those of Agrion, where they are but few ; and those of Phryganea, which are rather 
more simple. In the Flea (Pulew irritans), I have been unable to detect anything 
connected with this subject. i 
I have not been able to distinguish any difference between the sexes in reference to 
these structures, their relative size corresponding to that of the individual, which is 
generally larger in the female. The species of a given genus, especially of the Dipterous 
- group, exhibit a marked similarity in the appearance of these organs ; so that it is possible, 
by examining them, to tell to what genus any Fly, whose,halteres are presented to you, 
belongs. ' 
