﻿NEARCTIC SPECIES OF GASTERUPTIIDAE — TOWNES 89 



Psilaulacus Kieffer, Bull. Soc. Ent. France, 1910, p. 350. Type: Psilaulacus 

 annulalus Kieffer; first species included (by Kieffer, 1911). 



lAulacites Cockerell, Proc. U. S. Nat. Mus., vol. 51, p. 102, 1916. Type: 

 Aulacites secundus Cockerell; original designation. (New synonymy.) 



The charactei-s of this genus are outlined in the key to genera. The 

 Nearctic species bilobatus, editus, minor, and rufitarsis form a natural 

 group that Kieffer and others would segregate as the genus Odont- 

 aulacus, distinguished by having only two teeth on the tarsal claws. 

 But when this claw character is applied to exotic species some extra- 

 neous elements are added to the group, and for the present I include 

 them all in Aulacostethus without even a subgeneric separation. Other 

 natural groupings of the Nearctic species are not at present particu- 

 larly evident. Pristaulacus is the traditional name for most species 

 of this genus. Study of a specimen of the genotype of Aulacostethus 

 (at Cambridge) shows that this name must replace Pristaulacus. 



[key to the neartic species of aulacostethus 



1. Forewing black, with or without a yellow cross band 2 



Forewing hyaline, subhyaline, or suffused with reddish brown, with or without 

 dark spots or bands 3 



2. Forewing with a median yellowish cross band (fig. 15, a); tibiae and tarsi 



black 1. f asciatus Say 



Forewing entirely black ; tibiae and tarsi yellow 2. violaceus Bradley 



3. Forewing with the front half brown, most of rest subhyaline (fig. 15, h). 



3. torridus Bradley 

 Forewing colored otherwise 4 



4. Tarsal claws each with a submedian large tooth and a subbasal small tooth; 



forewing without spots 5 



Tarsal claws each with three to five teeth, of which the basal tooth is small; 

 forewing nearly always with a dark spot below stigma and often with a dark 

 apical mark (fig. 15, c-i) 8 



5. Hind femur black to dark brown 6 



Hind femur ferruginous to reddish brown 7 



6. Propleurum distinctly punctured; hind coxa and side of thorax rather opaque 



and rather finely sculptured; posterior half of top of head with dense fine 

 punctures; hind tarsus dark brown; apical half of female abdomen black; 

 first tergite (excluding the partly fused second tergite) of female about 1.3 

 as long as wide, of male about 1.45 as long as wide, 



18. bilobatus Provancher 

 Propleurum not distinctly punctured; hind coxa and side of thorax polished and 

 with moderately coarse sculpture; posterior half of top of head with sparse 

 fine punctures; hind tarsus stramineous to light brown; apical half of female 

 abdomen ferruginous, sometimes a little infuscate; first tergite (excluding 

 the partly fused second tergite) of female about 1.5 as long as wide, of male 

 about 1.9 as long as wide 19. rufitarsis Cresson 



7. Hind tibia concolorous with hind femur and hind tarsus, not darker than these; 



front and middle second trochanters and extreme bases of front and middle 

 femora brownish ferruginous; front and middle coxae and trochanters of 

 male usually ferruginous; anterior dorsolateral corners of mesoscutum some- 

 what angular; ovipositor sheath about 1.25 as long as forewing. 



20. editus Cresson 



