Composed of a square resonating body and a single string, the one-string violin known as the eeneg (or ee'neg) is used by the Comca'ac (Seri) communities of northeastern Mexico. This instrument is played with a bow, as a modification of the European violin. According to some ethnographic studies, the Comca'ac may have acquired it through indirect influence from their regional neighbors, the Yaqui, who retained the four-string violin. The instrument is regarded as belonging to men, who both make and play it. The eeneg is accompanied by song and does not appear together with other instruments; ritual musical pieces are intended to cure illness and are performed by shamans. Its use is also described, however, in recreational contexts.
The eeneg is made from the wood of white copal (Bursera hindsiana) or yellow amate (Ficus petiolaris), although the possible use of mesquite has also been recorded. Blocks of wood were carved until the body of the instrument was obtained; in more recent times, some musicians have used wooden panels assembled with nails. The instrument may include a metal plate, in addition to two or three perforations near the bridge that serve to produce the sound, or slots cut into the metal plate. At the upper end it carries a tuning peg.
According to Comca'ac musicians, in the past the eeneg was made entirely from natural materials. The string was therefore obtained from the tendons of deer, horse, cow, or pelican, as well as from badger intestine; there are even records of the use of sea turtle intestines. The string is attached to the base of the violin and today it is usually replaced by metal strings. The bow is made from mesquite wood, ocotillo (Fouquieria splendens), or a shrub known as “gobernadora” (Larrea tridentata), common in the Sonoran Desert. It measures less than 60 centimeters in length and is strung with horse hair from the tail; in the past, human hair was used.
Ethnographic records from the 1970s describe violins painted blue and red using motifs derived from facial painting, applied only to the sides and the pegbox. It appears, however, that these were violins intended for the tourist market, since personal instruments lack this type of decoration.