80 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



P' Raster with teges of 42-44 hamate setae scattered uregularly on 

 the venter of 10th abdominal segment, three or four long and slender 

 setae on each side. Lower anal lobe distinctly divided into two sub- 

 lobes placed close to each other. 



Ataenius sp. 4 



Material examined: Ten third-stage larvae collected at Edge- 

 water Golf Club, Chicago, 111., Sept. 11, 1951, by A. M. Radke 

 (USNM). 



Description: Maximum width of head capsule of third-stage larva 

 1.29-1.32 mm. Cranium light yellow, surface smooth except for two 

 depressions on each side on the frons. Three dorsoepicranial setae 

 and two microsensillae on each side. Frontal sutures distinct. Cly- 

 peus divided into preclypeus and postclypeus. 



Epipharynx with protophoba bistichous on left and monostichous 

 on right; protophoba with 16 microsensillae; mesophoba polj'-stichous. 

 Crepide small and subcircular; epitorma asymmetrical, flattened 

 apically and bent towards laeophoba. 



Mandibles light yellowish brown with scissorial and molar area 

 dark brown. Each mandible dorsally with two setae, ventrally with 

 two setae. Brustia equally developed on both the mandibles. 



Maxillary stridulatory area with an irregular row of 28-34 conical 

 teeth facing cephalad; small toothlike markings behind the plectrum 

 and on cardo. Galea ventrally with a long seta and a row of four 

 short setae. 



Abdominal segments 1-8 each with three dorsal annulets; each 

 annulet with a transverse row of setae except the last annulet of 

 segments 6-8. On the annulets of segments 1-5, each prescutum 

 with six short setae, each scutum with four long setae and three short 

 setae on each side, and each scutellum with 10 short setae. Abdom- 

 inal segments 7 and 8 broad; 9 and 10 narrow, each with two trans- 

 verse rows of closely placed setae but dorsa not divided. 



Raster with teges of 42-49 hamate setae curved at their distal 

 ends; two or three long and slender setae on each side. Lower anal 

 lobe divided into two sublobes placed adjacent to each other. 



Tribe Psammodiini 



This tribe is represented in the United States by four of the 10 

 known genera — Psammodius Fallen, Pleurophorus Mulsant, Trichior- 

 hyssemus Clouet, and Rhyssemus Mulsant. 



Species dealt with in this study include Psammodius oregonensis 

 Cartwright, Psammodius hydropicus Horn, Pleurophorus caesus 

 (Creutzer) and Pleurophorus longulus Cartwright. Larvae oiPleuro- 



