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§ XII. The Stink-clubs of the Female “ Maracuja Butterflies.” 1 
Plate J. 
The following paper deals with the female stink-glands in the genera 
Heliconius , Eueides , Golaenis [including Metamorpha ] and Dione ( Agrctulis) 
—bound together by the closest ties of blood-relationship — which, 
from the food-plant of their larvae, I unite under the term “ Mara- 
cupt butterflies.” A female belonging to any of these genera, when 
one takes hold of it, protrudes from the apex of the abdomen, on the 
dorsum between the penultimate and last segments, a large, yellowish, 
nauseous smelling gland (PL J., Fig, 1 W, Fig. 3 A, W) divided into a right 
and left convex half by a shallow furrow. The males of these butterflies 
possess, on the inner side of the anal valvulae, two smaller glands which 
emit the same scent. 
I observed a short time ago that a captured female of our beautiful 
green butterfly, Golaenis [. Metamorpha ] dido, when first seized, quickly 
extruded the large stink-gland in the usual manner. When the creature 
had become quiet and was then again disturbed or irritated, the gland was 
rather slowly exserted, and I then noted that the smell did not increase 
gradually, but suddenly was noticeably strengthened. It was then seen 
that this increase was due to the appearance of two tiny organs which I 
had hitherto overlooked—little stalked clubs, which might be compared to 
pins or to the halteres of Diptera , of which one is placed on each side of 
and beneath the stink-glands, on the posterior margin of the penultimate 
segment. One has only to cut off the apex of one of these stink-clubs in 
order to become convinced that the strengthened smell of the stink-gland 
really proceeds from them. 
The agreement between all the Maraeuja butterflies, in structure and 
mode of life, down to the smallest detail, led me to believe that the stink- 
clubs also would not be confined to a single species, and, as a matter of 
fact, I have found them in all those I was afterwards able to examine, 
namely, in addition to Golaenis \Metamorpha\ dido , in Heliconius apseudes, 
beschei and eucrate [narcaeai], Eueides Isabella , Dione juno , and vanillae. 
Thus these stink-clubs furnish further proof of the close relationship 
between four genera which have hitherto always been divided between 
the two sub-families of the Heliconinae and Nymphalinae , Eueides being 
1 Zeitschr. Wiss. Zool. , XXX. (1878), pp. 167-170. 
