Brachycentrus (Sphinctogaster) lateralis (Say 1823)

Brachycentrus (Sphinctogaster) lateralis (Say)

Phryganea lateralis Say, 1823:161.

Brachycentrus lateralis (Say).—Hagen, 1868:272.—Ross, 1944:265.—Fischer, 1970:103.

Sphinctogaster lutescens Provancher, 1877:262.

Brachycentrus lutescens (Provancher).—Ulmer, 1907:91.—Milne, 1936:123.—Fischer, 1970:104.

Brachycentrus incanus Hagen.—Leonard and Leonard 1949:28 [in error].

The identity of B. lateralis (Say) was established by Ross (1944) with the designation of a neotype, and full description of male, female, and larva. In describing Sphinctogaster lutescens, Provancher (1877) stated the holotype to be a male; Ross (1944) called it a female. Milne (1936) synonymized B. lutescens (Provancher) with B. lateralis Say; as this seems quite probable, I leave the name in synonymy.

The male genitalia place this species in close relationship to B. incanus Hagen. The tenth tergum is shorter, in dorsal aspect being wider than long, and in not having its apex angled dorsad. The clasper has a definite, though small, ventral area and the tip is blunter in lateral aspect, and in posteroventral aspect it is shorter and more nearly C-shaped with the apical point far from the lateral margin.

The larva is very distinctive in appearance, with its golden-yellow head bearing three (or rarely, five) narrow, longitudinal, black bands. A series of larvae from the Cacapon River, West Virginia, shows all gradations from three bands with a few dark granules posterior to the eye, through several degrees of completeness of this band, to the completely five-banded state. The mesal band, however, is always narrow, especially at the anterior of the frontoclypeus. The possible larvae of B. incanus Hagen are very similar, but they have five longitudinal black bands which are much broader than those of B. lateralis (Say), and several long setae on the ventral margin of the mid- and hindtibiae. Although the head coloration of B. appalachia, new species has five longitudinal, black bands and thus is similar to some examples of B. lateralis (Say), the species differs strikingly in the coloration of its legs.

ADULT.—Length of forewing, 6–8 mm, 9–11 mm. Color: male, body fuscous, forewing fuscous with pale flecks; female (and rarely males), body stramineous with fuscous head, tegulae, and a mesal, longitudinal band on meso- and metanotum, forewing pale grayish, with a slightly darker anterior margin. Male abdomen with seventh sternum bearing a broad posteromesal lobe about as long as broad.

Male Genitalia: Ninth segment without a sternal lobe. Cercus elongate, tapering apicad; cerci separated dorsomesally, mesal margins divergent posteriad. Tenth tergum elongate in lateral aspect with dorsal margin convex; in dorsal aspect almost twice as wide as long, tip very slightly excised mesally. Clasper with a distinct basal area in lateral aspect, tip bluntly rounded; in posteroventral aspect distinctly curved, mesal margin concave, apical point borne from near mesal margin.

LARVA.—Length to 11 mm. Sclerites bright golden yellow; head with a narrow, mesal, fuscous mark on frontoclypeus usually not reaching apex of frontoclypeus, with a narrow fuscous band on each gena adjacent to frontoclypeal suture (rarely with an additional dark band from eye to occiput); legs golden yellow, dorsal margins of femora of mid- and hindlegs with a black band. Femora of mid- and hindlegs with three enlarged setae; apico- and basodorsal setae barely enlarged over other dorsal setae; ventral margin with a uniform setal fringe. Mid- and hindtibiae with a single subbasal seta on ventral margin. Two submesal pairs of setae on first abdominal venter equal in size, but slightly larger than homologous setae on second segment. Lateral fringe present from third through seventh segments. Gills single, arising in dorsal, lateral, and ventral rows.

TYPE MATERIAL.—Neotype, male, INHS, P. lateralis Say, published as “Momence, Illinois: May 4, 1937, Ross & Mohr.” Type not seen; topotypes with same data studied.

Type, S. lutescens Provancher, location unknown if in existence; no data given, but probably Quebec. Type not seen.

MATERIAL EXAMINED.—USA, ILLINOIS, Momence, 4 May 1937, Ross and Mohr, 1 (INHS); same, but 17 May 1937, Ross and Burks, 3, 9 (INHS); same, but 14 Jul 1936, B.D. Burks, 5 larvae (INHS); same, but 31 Aug 1936, Ross and Burks, 10 larvae (INHS); same, but Kankakee River, 7 May 1940, B.D. Burks, 5 metamorphotypes, 1 pupa (INHS); same, but 27 Oct 1938, Ross and Burks, 5 larvae (INHS); same, but 21 Dec 1938, Mohr and Burks, 20 larvae (INHS).

[?ILLINOIS], Black Hawk, 2 May 1864, Walsh, 1 (MCZ).

MARYLAND, Allegany Co., North Branch Potomac River, Oldtown, 16 Aug 1982, W.L. Butler, 3 larvae (MWQMD).

MICHIGAN, Port Huron, Jun, H.G. Hubbard, 1. Detroit, H.J. Hubbard, 29, 2 (MCZ). Det. [?Detroit, Michigan], 26 May 1874, S. and H., 4, 1 (MCZ). Antrim Co., Manistee River, Rt. 618, 25 Oct 1966, N. Andresen, 1 larva (ROM).

PENNSYLVANIA, Harrisburg, 30 Apr, 3, 4 (MCZ).

SOUTH CAROLINA, Oconee Co., Chattooga River, Rt. 28, 18 Feb 1977, J.W. Chapin, 6 larvae (CUC); same, but 23 Mar 1978, 3 larvae (CUC); same, but 4 Apr 1976, 1 (CUC); same, but 9 Apr 1978, 1 prepupa, 1 pupa (CUC); same, but 10 Apr 1976, 3 metamorphotypes (CUC); same, but 14 Apr 1978, 2 (CUC); same, but 9 Sep 1976, 2 larvae (CUC); same, but 10 Nov 1976, 1 larva (CUC).

TENNESSEE, Blount Co., Little River, Rt. 73, Townsend, 14 Aug 1977, S. Prichard 12 larvae (CUC); same, but at Melrose Dam, 15 Apr 1981, W. Pennington, 1 prepupa, 4 pupae (UTK); same, but 30 Mar 1979, L. Snodderly, 5 larvae (UTK); same, but 1 mi. NW Melrose, 12 Apr 1977, Bryant, 2 (UTK); same, but Walland, 24 Apr 1973, Etnier and Poly, 9 (UTK). East Tennessee, Citico Creek, ∼3 mi. upstream from Little Tennessee River, 23 Apr 1966, D.A. Etnier, 3, 4 (UTK). Little Tennessee River at Citico Beach Rd., 15 Apr 1972, D.A. Etnier, 35, 7 (UTK).

VIRGINIA, Rappahannock River, Remington, 21 Mar 1940, Frison et al., 1 larva (INHS). Floyd Co., Little River, Rt. 615, north Floyd, 2 May 1978, C.M. and O.S. Flint, Jr., 5, 4; same, but 12 Apr 1974, D. Simonet, 1 (VPI); same, but 16 Apr 1977, J. Ray, 2 (VPI); same, but 21 Apr 1977, C.R. Parker, 15 (VPI). Bath Co., Jackson River, below Rt. 603 bridge, Jan 1973, R. Strickler, 1 larva.

WEST VIRGINIA, Cacapon River, Capon Bridge, 1 May 1944, Frison and Ross, 1 (INHS); same, but 0.5 mi. upstream of U.S. 50 bridge, 29 Oct 1971, Simmons and Hatcher (SCUBA diving, on Vallisneria), 6 larvae (CUC, USNM).

CANADA, ONTARIO, Cardinal, 14 Jun 1953, E.M. Walker, 5, 7 (ROM).

QUEBEC, Laprairie, 9 Jun 1926, F.P. Ide, 1 (MCZ); same, but 29 May 1957, 7 (ROM). Isle Ste. Hélène, Montreal, 2 Jun 1965, 1 metamorphotype (ROM); same, but 22 Aug 1964, 5 empty cases (ROM); same, but 28 Aug 1964, 1 decayed pupa with sclerites, 12 empty cases (ROM). Lachine Rapids [St. Lawrence River, near Montreal], 15 May 1965, F. DeLorme, 5 larvae (UMQ).

Brachycentrus lateralis is a species of humpless casemaker caddisfly in the family Brachycentridae. It is found in North America.