ON THE TRUE NATURE OF THE AZYGETHIDAE 
(CHILOPODA: GEOPHILOMORPHA)* 
By R. E. Crabill, jr. 
Smithsonian Institution, U. S. National Museum, Washington D. C. 
The family Azygethidae was proposed for the reception of a single 
genus and species, Azygethus at opus, by R. V. Chamberlin in his 
1920 study 1 of the Australian region’s myriopod fauna. The new 
group’s suprageneric rank was defended really on two grounds. The 
ultimate pedal segment reportedly had normal pleural sclerites, but 
even more remarkably this segment was said to bear a pair of spiracles. 
If the members of the genus did indeed all normally possess ultimate 
pedal segment spiracles, then their allocation to a new family would 
surely be justified, for they would thereby differ, not only from all 
other Geophilomorpha, but even from all other centipedes. 
This character was so extraordinary that, sixteen years later, At- 
tems expressed reservations as to its authenticity, and, regretting the 
total lack of figures, he urged that the specimen be re-examined. 
Nevertheless, in 1926 2 he did include Azygethidae in his treatment 
clearly implying his suspicion that the critical character might have 
been misrepresented originally. 
And there the matter has remained until the present. No subse- 
quent specimens of at opus have ever been discussed. No new species 
have ever been referred to the family. The original types have never 
been re-examined. In short, no corroborative evidence has ever been 
adduced in support of Chamberlin’s original interpretation. 
Furthermore, if we were to discount, for the moment, the spiracles 
and pleurites of the ultimate pedal segment and then attempt to 
imagine to what other family and genus the species could belong, our 
endeavor would prove fruitless. There are so many critical errors in 
the original description to lead one astray, that even a man of At- 
*This study was undertaken with the aid of a grant from the National 
Science Foundation and is published with the aid of a grant from the Museum 
of Comparative Zoology at Harvard College. 
The Myriopoda of the Australian Region, Bull. Mus. Comp. Zool. Harvard, 
64(1) : 32, (1920). 
2 Handbuch der Zoologie, Kukenthal and Krumbach, Bd. 4: 366, (1926). 
of families. Two years later he failed even to mention the name 3 , but 
'The Myriopoda of South Africa, Ann. South African Museum, 26, (1928). 
in his great monograph of 1929 4 he referred to the family again, 
4 Geophi!omorpha, in Das Tierreich, Lief. 52: 347, (1929). 
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