ABC was encouraged last week when its critically savaged new comedy "Cavemen" saw a slight bump in ratings for its third episode.

But hopes that the 8 p.m. show was gaining traction were punctured last night when the Geico-inspired sitcom fell to a season-low 2.2 overnight rating among viewers 18-49, attracting 6.54 million total viewers, good for fourth place on both counts.

Last night’s 2.2 was an 18.5 percent dropoff from a 2.7 overnight rating last week and off 33 percent from 3.3 earned for its premiere episode.

It also contributed to an 11 percent week-to-week slide for ABC’s 8:30 p.m. sitcom "Carpoolers," which posted a 2.4 overnight rating among 18-49s last night, a week after posting a 2.7.

But at least that show was able to show a week-to-week gain among total viewers, albeit a slight one, rising from 6.96 million last week to 7.13 million last night.

The same can’t be said for "Cavemen." It slipped 5 percent week-to-week among total viewers from last week’s 6.92 million.

Media people expected "Cavemen" to launch fairly well, which is did, before falling into a slide, which it has. But one good thing about the 8 p.m. comedy hour for ABC is that it doesn’t seem to be affecting the 9 p.m. "Dancing with the Stars" results show.

Last night "Stars" posted a 4.4 overnight rating among 18-49s, up slightly versus last week’s 4.3.

Fox finished first for the night with a 5.4 average overnight rating and a 14 share. NBC was second at 3.5/9, ABC third at 3.2/8, CBS fourth at 2.9/8, Univision fifth at 1.5/4 and CW sixth at 1.4/4.

CBS started the night in the lead with a 3.7 at 8 p.m. for "NCIS," followed by Fox with a 3.1 for "Bones." NBC was third with a 2.6 average for "The Singing Bee" (2.3) and its first half hour of "The Biggest Loser," ABC fourth with a 2.3 average for "Cavemen" (2.2) and "Carpoolers" (2.4), CW fifth with a 1.6 for "Beauty and the Geek" and Univision sixth with a 1.1 for "Amar sin Limites."

At 9 p.m. Fox took the lead with a 7.6 for "House," while ABC jumped to second with a 4.4 for its "Dancing with the Stars" results show. NBC was third with a 3.3 for its last hour of "Biggest Loser," CBS fourth with a 3.0 for "The Unit," Univision fifth with a 2.3 for "Destilando Amor" and CW sixth with a 1.2 for "Reaper."

NBC led the 10 p.m. hour with a 4.7 for "Law & Order: Special Victims Unit," with ABC second with a 2.8 for a "20/20" special covering the California wildfires. CBS was third with a 2.0 for "Cane" and Univision fourth with a 1.2 for "S.O.S. Sexo y Otros Secretos."

Among households, Fox led the night with an 8.1 average overnight rating and a 12 share. ABC was second at 7.9/13, CBS third at 7.7/12, NBC fourth at 5.9/9 and Univision and CW tied for fifth at 1.9/3.