A NEW DAMOTHUS 
AND A KEY TO THE NORTH AMERICAN 
DIGNATHODONTID GENERA 
(CHILOPODA : GEOPHILOMORPHA : 
DIGNATHODONTIDAE) 1 
By R. E. Crabill, jr. 
U. S. National Museum, Washington, D. C. 
The genus Damothus was proposed by R. V. Chamberlin in i960 
(p. 239) for the reception of a single species, month, which had been 
collected in the Wasatch Mountains of Utah. While collecting arach- 
nids and myriapods at Ophir in the Oquirrh Mountains of that State, 
Dr. H. W. Levi unwittingly uncovered the second-known specimen 
of the genus, which I judge to represent a new species, alastus, here 
described. I wish to express my thanks to Dr. Levi for his kindness in 
placing this and much other valuable material in my hands for study. 
On the basis of all available information, the two most distinctive 
features of the genus are the massively crassate and essentially tubular 
ultimate legs of the male, and the presence of two basal denticles 
on the prehensorial tarsungula. Indeed, the latter character alone will 
distinguish Damothus from all other known chilopod genera of what- 
ever order. After more is known about Damothus , it may well be seen 
that two other features have significance diagnostically: the peculiar 
shape of the 1st maxillary medial lobes; the relatively strongly- 
developed labral sidepieces. 
Comparing the Harvard specimen with Dr. Chamberlin’s original 
description of month, I find the following to be significant distinguish- 
ing features. D. month : (1) The first maxillae are without lappets. 
(2) The coxopleural pores are concentrated along and mostly con- 
cealed beneath the margins of the ultimate pedal sternite. (3) Ventral 
pore-fields are absent. D. alastus, n. sp. : (1) The first maxillary 
coxosternum bears a pair of conspicuous and relatively long lappets. 
(2) The coxopleural pores are all exposed and are not concentrated 
along and beneath the ultimate pedal sternite. (3) Small but con- 
spicuous pore-fields are present on all pedal sternites except the last. 
This study was undertaken with the assistance of a grant from the National 
Science Foundation. 
Manuscript received by the editor January 30, 1962. 
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