NO. 3568 MELANOTUS — QUATE AND THOMPSON 49 



28. Melanotus tenax (Say) 

 Figures 6d, llo; Plate Im 



Elater tenax Say, 1839, p. 185. 

 Cratonychiis tenax. — LeConte, 1853, p. 479. 



Melanotus tenax. — Candfeze, 1860, p. 360. — Blatchley, 1910, p. 755. — Thomas, 

 1941, p. 260.— Dietrich, 1945, p. 58.— Fattig, 1951, p. 21. 



Male. — Body color reddish to dark reddish brown, covered with 

 white or yellow vestiture, evenly distributed over body. 



Head: Front with pair of shallow anterolateral transverse de- 

 pressions, margin dark reddish brown, not strongly protuberant above 

 clypeus, thinner in center, evenly rounded or a little flattened an- 

 teriorly when viewed from above; parantennal fovea smaller than 

 trapezoideus, well defined, circular; nasale slightly raised, width equal 

 to IK times height. Mandible with deep, teardrop-shaped pit. 

 Antenna exceeds tip of hind angle by one-half segment, reddish 

 brown, ratio of segments 2:3:4=4:6:9, segment 4 about twice as 

 long as maximum width; erect male hairs short and dense. 



Pronotum as wide as or little wider than long; punctures at center 

 usually separated by distance equal to own diameter, subequal to 

 those on front; sides of pronotum straight, subparaUel; hind angles 

 slightly divergent, carina usually extending well cephalad of base of 

 hind angle. Genitalia as figured; paramere without apical blade. 



Elytron: 5.5 ±0.3 mm (5.2-6.3). 15 spec. 



Female. — Antenna not extending to tip of hind angle; internal 

 genitalia as figured, bursa with about 50 peglike spines, elongate and 

 enlarged at base of accessory gland, gland short and clavate. 



Elytron: 5.0-6.2 mm. 4 spec. 



Types. — Types of tenax: "Mass." Specimens lost. 



Distribution. — New York south to Georgia and west to Illinois. 



Georgia: Houston; June. Illinois: Greene; June. Maryland: Prince 

 Georges; June. Massachusetts: Middlesex, Nantucket; June. New York: 

 Albany; June. North Carolina: Craven; May. South Carolina: Berkeley; 

 April. 



M. trapezoideus and the tenax can be distinguished from other 

 species of the americanus group by their small size, large pronotal 

 punctures, and large parantennal fovea. The two are separable by 

 characters in the key. Also, the pronotum of trapezoideus is usually 

 flatter and the sides more markedly divergent than in tenax. The 

 female internal genitalia are dissimilar; the chief differences are the 

 unusual swelling of the bursa at the base of the accessory gland and 

 the midlateral origin of the sperm athecal duct of tenax, but not in 

 trapezoideus. Unlike most species of Melanotus, the male genitalia 

 of these species appear indistinguishable and are not of value in 

 separating the two. 



