The Anatomy of Ants. By Sir John Lubhoclc, Bart. 129 
peduncle (known as the scale or knot) between the metathorax and 
the remainder of the abdomen. In the Myrmicidae two segments 
are thus detached from the rest. Forel indeed considers this latter 
portion as alone constituting the abdomen — or rather speaks as if 
he did. “ Nous appellerons done,” he says, “ premier segment de 
l’abdomen, le second segment reel des deux premieres sousfamilles, 
et le troisieme segment reel des Myrmicidae.” This seems to 
me an ambiguous, and therefore inconvenient system of nomen- 
clature. 
The Poneridae form, as regards the peduncle, and in some other 
respects, an intermediate group between the Formicidae and the 
Myrmicidae. The second abdominal segment is contracted pos- 
teriorly, but not so much so as to form a distinct knot. 
The form of the knot offers in many cases valuable specific 
characters. 
I have sometimes been tempted to correlate the existence of a 
second knot among the Myrmicidae with their power of stinging, 
which is wanting in the Formicidae. Though the principal mobility 
of the abdomen is given in the former, as in the latter, by the joint 
between the metathorax and the knot, still the second segment of 
the peduncle must increase the flexibility, which would seem to be 
a special advantage to those species which have a sting. It must 
indeed be admitted that (Ecophylla * has a sting, and yet only one 
knot ; but this, of course, does not altogether negative my sugges- 
tion, which, however, I only throw out for consideration. 
The knot is provided with a pair of spiracles, which, however, 
are situated, as Forel states, in the front of the segment, and not 
behind, as supposed by Latreille. 
In most entomological works it is stated that the Myrmicidae 
have a sting, and that, on the contrary, the Formicidae do not possess 
one. The latter family, however, possess a rudimentary structure 
representing the sting, but it seems merely to serve as a support for 
the poison duct. Dr. Dewitz, who has recently published | an 
interesting memoir on the subject, denies that the sting in Formi- 
cidae is a reduced organ, and considers it rather as in an undeveloped 
condition. The ancestral Hymenoptera aculeata, in his opinion, 
had a large poison apparatus, with a chitinous support like that 
now present in Formica, from which the formidable weapons of 
the bees, wasps, and Myrmicidae have been gradually developed. 
I confess that I am rather disposed, on the contrary, to regard the 
condition of the organ in Formica as a case of retrogression 
contingent upon disuse. I find it difficult to suppose that organs 
— so complex, and yet so similar — as the stings of ants, bees, 
and wasps, should have been developed independently. On the 
* ‘Proc. Linn. Soc.,’ vol. v. p. 101. 
t ‘Zeit. f. Wiss. Zool.,’ vol. xxviii. p. 527. 
