Laccophilus biguttatus Kirby 1837

Laccophilus biguttatus Kirby (Figs. 201-208, 321)
Laccophilus biguttatus Kirby, 1837, p. 69. Type: British Museum (Natural
History), Boreal America; Leng, 1920, p. 77; Zimmermann, 1920, p. 25;
Balfour-Browne, L, 1944, p. 345; Blackwelder and Blackwelder, 1948, p. 3. Laccophilus inconspicuus Fall, 1917, p. 164; Leng, 1920, p. 76; Zimmermann,
1920, p. 25.
DIAGNOSIS. — This is the only Laccophilus occurring in North America with a pale unicolorous or concolorous elytra. All others are irrorated, variegated, marmorated or spotted, or much darker. It resembles L. niexicanus, an irrorated species, but lacks a file in the male. L. biguttatus also his thickened, darkened antennal segments, a character possessed as well by the strongly patterned undatus.
DESCRIPTION. — Medium (length, 3.9 to 4.8 mm; width, 2.3 to 2.6 mm), concolorous, brownish-yellow, non-irrorated species; metacoxal file absent, prosternal process short; ovipositor sawlike. COLOR. Head: generally brownishyellow above and beneath, but darker on occiput, brownish on tips of maxillary and labial palpi and on the distal halves of the last seven antennal segments.
Pronotum: about the same as head and with a darker area on the anterior margin corresponding to the one on the head. Elytra: generally unicolorous light brownish-yellow to light brown; some suggestion of pattern along the anterior half of the lateral margins, subbasally, and just behind the middle; epipleura entirely pale. Tergite VIII: light to medium brown. Venter: variable from entirely brownish-yellow to nearly reddish-black or black; legs usually remain pale yellowish-brown tinged with red. Genitalia: variable in the same fashion as the venter. ANATOMY. Microreticulation: faintly double on the head and pronotum, but individual cellules strongly impressed; single on the elytra; surface shining. Head: antennal joints thicker than other North American Laccophilus; supraclypeal seam parallel, but separated somewhat from the margin. Pronotum: WH/PW, 0.68; LP/PW, 0.40. Elytra: apices slightly truncated; female epipleura without flange. Venter: prosternal process with well-defined crest from base to apex; postcoxal processes rounded and laterally projecting well posterior to midline; last ventral abdominal segments in both sexes neither produced nor truncated; median crest on female segment marked and rooflike at apex: male crest nearly symmetrical so that the outline is similar in the two sexes; scattered setigerous punctures. Legs: male proand mesotarsi enlarged slightly in a dorsoventral plane; palettes easily visible at 20 power magnification; fifth tarsal segment on both pair of front legs about one and three-fifths as long as corresponding fourth; setae on profemoral margin (7 or 8) similar in diameter, length and number to mesofemoral ones. Genitalia: oval plate produced to point; its median crest with leftward curvature; somewhat stronger than the raised lines which are present on either side; aedeagus strongly curved at about half its length, expanding before the apex, but narrowing near tip; setae projecting from apex of right paramere instead of subapically as in most members of the genus; ovipositor with about 15 sawlike teeth on each row.
NOMENCLATURAL NOTES. — The biguttatusol Kirby (1837) was long unrecognized and was ascribed to fasciatus or proximus. Sharp's (1882a) monograph does not include the species. Fall's inconspicuus was recognized as a synonym by J. Balfour-Browne ( 1944) ; and, at the same time, its identity was clarified. Kirby's description noted the darkened antennal segments and palpi; but his references to spots (that are weak at best and, perhaps, partly due to translucence ) delayed the recognition of this distinctive species.
L. biguttatus is strongly similar to L. minutus (L. ) of the Old World, as noted by Kirby, and, eventually, may prove to be a race of an extremely widespread polytypic species. The genitalia, thickened and darkened antennae, lack of file, microreticulation, size, and shape are all close; and only the elytral pattern differs. The last is a feature that varies considerably in other races of several North American species. VARIATION. — The venter varies from pale yellowish-brown to nearly all black in some specimens. This feature is not clearly geographic, but is generally uniform for any one sample.
Females appear to be slightly larger than males, but with a large overlap ( Table 18). The peak in the frequency distribution of length for females is about 4.4 mm, and that for males is about 4.25 mm (fig. 22). The largest females are slightly larger than the largest males, and the same relationship holds for the smallest of each sex as well. In samples from six different areas females always had larger values than the males from the same locality.
Quantitative comparisons of seven samples from New Hampshire to the Yukon give no indication of any racial differentiation of biguttatus within North America. Differences appear to be more local
TOTAL LENGTH (mm) in Crosshatch; females, stippled.
than regional. The three largest and most reliable samples (from Manitoba, Alberta, and from Colorado) are similar. Males from the Yukon (n = 9) do appear to be smaller than all other males, except those from New Hampshire ( n = 3 ) , and may reflect the extreme environment of the northern climate.
— This is the only boreal species of Laccophilus in North America. It occurs in all the northern tier of states and as far south as northwestern New Mexico and the Sierra Nevadas of California. It is known from all provinces from Quebec west. It is not known how far north the range extends in eastern Canada; but it does occur in the Northwest Territories, the Yukon, and Alaska (fig. 21).
L. biguttatus seems to be the commonest Laccophilus in the interior provinces. I have collected this species only in the Chuska Mountains of northwestern New Mexico and at an altitude of about 9000 feet. It was in mountain meadow ponds that were choked with water weed and algae, but with clear water. Fall quotes Sherman that, in New Hampshire, they are taken at higher altitudes of the White Mountains. In North Dakota, Wisconsin and Michigan, they had to be taken at much lower altitudes than the two previously cited localities. CANADA. — ALBERTA. Calgary, Calgary, 1, x.23.27, O. Bryant (CAS). Cypress Hills, 1, viii.25.27 (USNM); 1 5, vi. 13.24 (DAV). Edmonton, 2 paratypes (inconspicuus Fall); 4, iv.12.17; 14, iv.22.17, F. S. Carr (USNM); 19, iv.4.18, F. S. Carr; 30, viii.19.27, O. Bryant; 4, vi.12.17, F. S. Carr (CAS). 2 3,2 2, v.5.15; 3 3, iv.9.17; 2 6, iv.11.17; 1 3, v.20.17; 13,12, iv.27.18, F. S. Carr (MCZ). High River, 1, vi.25.27, O. Bryant (CAS). Medicine Hat, 1 $, viii.21.23, F. S. Carr (FM); 1, vii.29.— , H. J. Rayner (CAS). Red Deer, 1, vii.19. — (USNM). Tofield, 1, x.24.24; Turner Valley, 25, v.24.29, O. Bryant (CAS). Waghorn, 10 (USNM). Wastoc, 1 3 , x. 12.21, F. S. Carr (DAV). BRITISH COLUMBIA. Clinton, 2, vi. 18.31, R. Hopping; 2, x. 11.43, H. B. Leech & C. V. Morgan; Copper Mtn., 1, v. 15.43, G. S. Smith; Enderly, 1, iv.1.45, H. B. Leech; Fernie, 11, ix.16.28, O. Bryant; Lumby, 1, v.11.33, E. R. Backell (CAS). Lac Le Hache, 3 3 , viii. — .59, J. Robertson (LACM). Nicole Lake, 1 3, viii.25.32, A. E. Thrupp (BERK); 3, viii.25.32, A. Thrupp; Oliver, iv.25.33, E. R. Backell (CAS). Paxton Valley, 1 2, vi.22.23, A. E. Thrupp (BERK); 6, vii.22.53, A. E. Thrupp (CAS); 1 3, vi.22.23 (LACM). Similkameen, Taylor Swamp, 2, iii.29.41, High (CNL); Similkameen, 2, iii. 29.41, H. B. Leech; Upper Hat Ck., 1, viii.25.32; 1, viii.29.33, G. J. Spencer (CAS). Vernon, 2 3,5 2, ix.2.40, H. B. Leech (LACM). DISTRICT OF MACKENZIE. Aklavik, 3, viii.5.30; 2, ix.5.30; Hay River, 3, ix.30.29; 16, vii.12.30, O. Bryant (CAS). MANITOBA. Aweme, 7, vi. 16.04, Criddle; Piquitenay, 2, vii.24.17, J. B. Wallis (USNM). Stonewall, 1, v.11.24, J. B. Wallis (CNL). Treesbank, 11 3, 8 2, vii. 10.25, J. B. Wallis (AMNH); 8 3, 12 2, vii. 10.25 (MCZ). Winnipeg, 6, viii. 16. 16: 2, v. 27. 24, J. B. Wallis (USNM); 1, v.4.24,
J. B. Wallis (CNL); 1 3, ix.2.16, J. B. Wallis (CNG); 1 9, v.l.— ; 13,19, v.8.— , J. B. Wallis (AMNH); 1 3, viii.16.16, J. B. Wallis (CAS). ONTABIO. Nipigon, 1 9, viii.29.27, Darlington (MCZ). Sioux Lookout, 1<?,19, ix.5.16 (CNG). QUEBEC. Abitibi Post, 5, vii.23.35; Duparquet, 4, viii.2.35; 3, v.15.38; 5, viii.28.39; 5, vii.21.43; 1, ix.2.43, G. Stace Smith (CAS). Montreal, 3 (USNM); 2 3,2 9, vii.— .— , Chagnon (AMNH). Notoshquan, 1, xi.8.29, W. J. Brown (CAS). Strathcone, 1, v.— .05 (USNM). SASKATCHEWAN. Lost Mtn. Lake, 1, JST (CNL). Murray (Lake?), NW. of Battleford, 1, v.28.39 (CNL). Redberry Lake, 2, vi.24.39; Redvers, 2 (CNL); 1 3 (MCZ). Regina, 1, v.30.38, C. Shaw (CAS); 1 3, iv. 15.44, C. C. Shaw (MCZ). Sturgeon (Lake?), 2, vi.24.39 (CNL). Yorkton, 14, vi.5.47, C. C. Shaw (CAS);
I 9, iv.24.45, C. C. Shaw (MCZ). YUKON. Mayo, 6 3,5 9, vii.3.55, F. S. Carr (CARR).
UNITED STATES OF AMERICA. — ALASKA. Fairbanks, 2 9, viii.4.58, Lindroth (CAS); Fairbanks, Farmers' Loop, 2 9, viii.11.57; Glenn Hwy., Mile Post 86, 1 3, viii.28.57; Alaska Hwy., Mile Post 1370, 1 3, viii. 10.57, E. L. Kessel (CAS). CALIFORNIA. Tulare County. Sequoia Natl. Park, 1 3, F. E. Winters (CAS). COLORADO. Boulder, Grant or Larimer Counties. Battle Mtn. Dam, 15, vii.17.37, E. B. Andrews (CAS). Rocky M.N.P., Glacier Basin, 2, vii.— .37, E. B. Andrews (CNL); 2, vii.1.37 (USNM); 3 9, vii. 1.37, H. B. Leech (FM); 2 3, vii.1.37, J. G. Thorndike (AMNH). R.M.N.P., 8500 feet, 1, F. E. Winters (CNL); Storm Pass, 3, vii.8.38, E. B. Andrews (CAS). Glacier Basin, 2 3, viii.1.37, Andrews (MCZ). Rocky M.N.P.,
II 3, 10 9, F. E. Winters (CAS). Jackson County. Cameron Pass, 15, viii. 19.41, H. P. Chandler (CAS). Muddy Pass Jet., Hwy. 40, 2 3, 2 9, vii.3.63, R. D. Anderson (RDA). Pinegrass Pk., 1, viii. 8.25, Statterthwait (USNM). Park County. Kenosha Pass, 10,000 feet, 3, vii. 16.38, J. W. Green (CAS). MICHIGAN. Cheyboygan County. Smith's Bog, 1 3 , vii.5.52, P. J. Spangler (USNM). Livingston County. E. S. George Reserve, 7, vi. 10.50, F. N. Young (CAS). Marquette County. Marquette, 7, vii. 1-2. 16 (USNM); 1 9, vii.2.16, J. D. Sherman, Jr., (AMNH). MONTANA. Carbon County. E. Rosebud L., 1 9, vi.19.61 (DAV). NEW YORK. Essex County. Mt. Marcy, L. Tear, 1 (USNM). Tompkins County. Ithaca, 4, vi.9.17; 2, vi.17.17; 2, v.21.26, H. Dietrich (CNL). NEW HAMPSHIRE. Coos County. Mt. Washington, 1 (USNM). Peabody Spring, 5000 feet, 1 9, ix.— .— , J. Sherman, Jr. (AMNH). Starr L., 4800 feet, 1 (USNM). Storm L., 4930 feet, 1 (USNM). Crafton County. Rumney, 1 3,2 9, iv.21.16; 1 3,1 9, iv.22.16; 1 3, iv. 17. 27, Darlington (MCZ). NEW MEXICO. San Juan County. Chuska Mtns., Washington Pass, 9000 feet, 50 + , x.5.68, JRZ (NMSU). NORTH DAKOTA. Benson County. Ft. Totten Lake, 8, vi.21.21, C. K. Sibley; 14, viii.22.20 (CNL). Bottineau County. Turtle Mtns., Fish Lake, 8, vii. 13.21; L. Metigishe, 1, vii.22.21; Dion Lake, vii. 15.21, C. K. Sibley (CNL). Ramsey County. Devil's Lake, S. Odessa Pond, 1, vii.5.21: N. Odessa Pond, 1, viii.5.21, C. K. Sibley (CNL) . VERMONT. Chittenden County. Mt. Mansfield, Lake Cloud,
LACCOPHILUS LEECHI a
leechi, and L. youngi.
1, iv.19.13 (USNM). WISCONSIN. Oneida County. Three Lakes, 11, 1, ix.__.04 (USNM); 3 <J , 1 9, W. S. Marshall (AMNH). WYOMING. Yellowstone Natl. Park, 8000 feet, 1 9, viii. 17.33, E. B. Andrews (CAS).

Laccophilus biguttatus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America and the Palearctic.