Rhagio costatus (Loew 1862)

Rhagio costatus Loew (PI. I. fig. 5; pi. II. fig. 12)
1862. Leptis costata Loew, Berl. Ent. Zeits. vi, p. 187. 1908. Rhagio costatus Kertesz, Cat. Dip. in, p. 304.
Brownish yellow; thorax with three, more or less well defined, broad, brownish stripes, narrowly separated; abdomen with a somewhat elongate brownish to blackish spot on each segment above; legs somewhat variable, brownish yellow to fuscous, the hind pair usually darker than the first two; wings slightly cloudy, on costal margin brownish yellow; stigma pale brownish.
Male. — Length, 12 to 14 mm. Head. Face brownish pollinose, sides with pale hairs; palpi and proboscis brownish yellow, the former with moderately long pale hairs; antennae brownish yellow, the arista fuscous.
Thorax: Brownish yellow except three very broad fuscous stripes above, the middle one of which is often narrowly divided and in some individuals is darker and more pronounced than in others; pleura on lower half and a more or less distinct spot at base of scutellum darker. Thorax with sparse short black hairs, more numerous and longer on lateral and caudal borders and on scutellum. Halteres yellowish, knobs sometimes somewhat infuscated.
Abdomen: Brownish yellow, each segment with a dark brownish or fuscous elon
gate spot, usually broader behind, on median line and a triangular one on either side on lateral border; with rather short fairly numerous black hairs, on sides becoming longer, thicker and pale.
Legs: Brownish yellow; middle and hind coxae more or less brownish, front and middle femora on apical half, and posterior femora and tibiae usually more or less infuscated; tarsi fuscous.
Wings: Membrane wholly faintly suffused with pale brownish; veins brownish; cells on costal border strongly tinged with brownish yellow; stigma elongate and slightly darker.
Female. — Length, 14 mm. Similar to male with the following exceptions: Front light brown pollinose; in ground color and markings generally somewhat paler; thoracic markings almost obsolete; lower half of pleura not brownish; abdominal markings less distinct; legs, except tarsi, almost uniform brownish yellow.
Specimens Examined: About 41 males and females.
Washington: i o i 9, Seattle, [Univ. Wash.].
Oregon: i d Corvallis, April 24, 1897, [U. S. N. M.]; 1 9, Corvallis, June 5, California: 2 d 3 9 , Mesa Grande, Sonoma County, June 1908, (J. P. Baumberger), [A. N. S. P.]. 5 d 2 9, Marin County, [A. M. N. H., "Hy. Edwards, no. 656"]; 1 9 , Marin County, (E. C. Van Dyke), [U. S. N. M.]. 2 d 3 9 , Sonoma County, [Brooklyn Mus., Ace. no. 11941]. 2 d Inverness, May 23, 1910, (E. C. Van Dyke), [U. of Cal.]. 1 9 , Napa County, (E. C. Van Dyke), [U. of Cal.]. 1 <? Lagunita, [A. M. N. H., "Hy. Edwards, 656"]. 1 d>, Baron; 1 d I 9, Lake County; 1 cf, Sausalito, May 13, (J. C. Thompson); 1 9, Fieldbrook, May 29, 1903, (H. S. Barber); 1 d Humboldt County, (E. C. Van Dyke), all U. S. N. M.]. 8 cf , Muir Woods and Berkeley, May 18, 19, 28, [M. C. Van Duzee]. 1 tf , Muir Woods, Marvin County, May 21, 1916, (M. C. Van Duzee), [A. N. S. P.].
This is one of the largest species of the genus. It may be readily distinguished by its large size, the abdominal markings and the strong yelloAvish tinge on the costal border of the wings. It is apparently not uncommon in California.
A male received from F. R. Cole, without a locality label but presumably from California has the abdominal spots produced on either side as broad blackish bands reaching across the base of each segment. It is undoubtedly referable to this species however.