158 "U- S. NATIONAL MUSEUM BULLETIN 209 



segment of flagellum about 3.2 as long as wide, the penultimate seg- 

 ment about 1.9 as long as wide; mesopleuron mat, with fine close 

 punctures, its pubescence of moderate length, whitish and conspicu- 

 ous; squama of genitalia unusually narrow and with an unusually 

 strong median ventral protuberance. 



Female: Forewing 5.0 to 7.0 mm. long; clothing hairs of frons pale, 

 faintly broader and more conspicuous than in A. nigrellus and A. 

 architectus, arising from fine subadjacent punctures on a mat back- 

 ground; apical margin of clypeus broadly angled to a weak median 

 point; second flagellar segment about 3.7 as long as wide; venation of 

 forcAving as noted in the key; groove of pronotum without distinct 

 cross wrinkles; pygidial area pohshed, without evident punctures. 



Coloration of both sexes blackish brown with a weak (male) or 

 strong (female) greenish blue iridescence which is strongest on the 

 thorax; head, antenna, mouth parts, legs, and abdomen with variable 

 amounts of fulvous coloration, according to the subspecies; tegula 

 light brown. Male with the apical half of mandible, clypeus except 

 for a median spot, face except for a median spot, lower lateral corners 

 of frons, and a large median spot on the last tergite, white. Female 

 with the apical half of the mandible fulvous. 



This is one of three Nearctic species with blackish legs and body 

 with a bluish or greenish iridescence, the other two being architectus 

 and nigrellus. Males are easily separated, but the females with difli- 

 culty. Some females of the present species have the legs partly ful- 

 vous and these are easily recognized as belonging here, since neither 

 architectus nor nigrellus ever have the legs thus marked. Females of 

 caerulescens without fulvous on the legs are difiicult and often impos- 

 sible to differentiate. (See the comparisons of the three species in the 

 key to females.) 



There are three subspecies as indicated below. 



8a. Auplopus caerulescens subcorticalis (Walsh) 



Agenia subcorticalis Walsh, 1869, Amer. Ent., vol. 1, p. 162, cf, 9. Types: 

 cf, 9, ?Illinois (lost). 



Pseudagenia antennalis Banks, 1910, Psyche, vol. 17, p. 251, 9 • Type: 9 , 

 Fedor, Lee County, Tex., May 29, Birkmann (Cambridge). 



Pseudagenia ariella Banks, 1941, Canadian Ent., vol. 73, p. 122, [9] (new syn- 

 onymy). Lectotype: 9, Tempe, Ariz., Aug. 1, J. Bequaert (Cambridge). 



Marked with fulvous stains on antenna, front femur, tibia, tarsus, 

 and apex of coxa. The fulvous markings are often extensive, approach- 

 ing those of the subspecies caerulescens. The arbitrary division be- 

 tween the two is whether the middle femur is mostly blackish (sub- 

 species subcorticalis) or fulvous (subspecies caerulescens). 



Specimens (24 cf, 449): From Arizona (Tempe and Tucson); 

 British Columbia (Salmon Arm); Cahfornia (Needles); Colorado 



