Centipede Subfamily Plutoniuminae 73 



this article and is an available genus-group name even though it lacks 

 a type species. It is one of the rare genus-group names lacking a 

 genotype, the only one I know of in myriapods. 



Diagnosis. With nine pairs of spiracles, on segments 3, 5, 8, 

 10, 12, 14, 16, 18, and 20. 



Distribution. Coastal Croatia and Montenegro, Bosnia-Hercegovina, 

 Spain, and Portugal; eastern North America from western New England 

 and the vicinity of Chicago, Illinois, to the south Florida Keys and 

 nearly to Corpus Christi, Texas, ranging westward to the eastern border 

 of the Central Plains in Oklahoma and onto the Edwards Plateau in 

 Texas; and western North America from western Chihuahua and southern 

 Sonora, Mexico, to the Pacific Ocean in California and northern Baja 

 California Norte, north to southern Nevada, southwestern Utah, and 

 southwestern Oregon (Fig. 10). 



Species. Five, as distinguished in the following key, adapted from 

 those in Attems (1930), Chamberlin (1951/?), and Weaver (1982). 



Remarks. Sutural differences on the ultimate tergite deserve emphasis. 

 Every specimen of T. posticus and T. phanus that I examined displayed 

 a complete median suture running the entire length of the tergite from 

 the anterior to the posterior edges; conversely nearly every individual 

 of T. spinicaudus lacked the suture, but occasional specimens have 

 minute, barely detectable remnants from the anterior margins. For practical 

 purposes, T. spinicaudus can be characterized as lacking the suture 

 because these occasional remnants extend no more than 1/32-1/16 of 

 the tergal length. The other species, T. californiensis and T. erythro- 

 cephalus, typically possess incomplete median sutures that extend caudad 

 from the anterior margin but terminate or fade out just before the 

 caudal edge. Rarely in these species does the suture extend the entire 

 length of the tergite. 



Key to Species of Theatops 



1. European species, occurring in Portugal, Spain, Croatia, Bosnia- 



Hercegovina and Montenegro ...erythrocephalus (C. L. Koch) 

 North American species 2 



2. Ultimate prefemora with dorsal distomedial spurs (Figs. 7-9) ... 3 

 Ultimate prefemora without dorsal spurs (Fig. 6) 4 



3. Ultimate tergite with complete longitudinal, midline suture dorsally 



(Figs. 33-34); central and western Texas phanus 



Chamberlin 

 Ultimate tergite without midline suture or with only minute remnant 

 anteriad (Figs. 7-9); eastern United States from northern Illinois 

 and central Iowa to southwestern Arkansas, and from northwestern 



