Moneilema gigas are endemic to the deserts of the Southwestern United States and northern Mexico. These beetles are large (up to about 5 cm excluding antennae) and shiny black. There is a light-grey ring on the fourth segment of the long antennae. The elytra are fused to a hardened shell, and the beetles are unable to fly.
The preferred hosts are chollas and prickly pears (Genus Opuntia). Adults are often seen feeding on soft portions of the cactus. Eggs are laid near the base of the plant, and larvae feed on both roots and stems (Linsley & Chemsak 1984, Phillips & Comus 2000).
Moneilema gigas is a large, flightless, black beetle native to the Sonoran desert at elevations below 1500 metres.[1] The front wings are fused forming a single, hardened shell. Collectively - with 19 other Moneilema species - M. gigas is also known as the cactus longhorn beetle.
Moneilema gigas normally feeds on chollas and prickly pear cacti, and is known to feed on saguaro seedlings. Larvae bore into cactus roots and stems, sometimes killing more susceptible individuals. Adults also feed on the surface of cacti.[2] M. gigas are most active during mid or late summer - the adults typically emerging during the summer monsoon season.
Like many flightless beetles, these beetles have limited wing musculature with a rounded abdomen and thorax, similar in appearance to a number of other flightless desert beetles. Cactus longhorn beetles resemble and mimic the behavior of noxious stink beetles in the genus Eleodes.[3]
Moneilema gigas, Pima County, Arizona 
Moneilema gigas, Pima County, Arizona Wikispecies has information related to Moneilema gigas. Moneilema gigas is a large, flightless, black beetle native to the Sonoran desert at elevations below 1500 metres. The front wings are fused forming a single, hardened shell. Collectively - with 19 other Moneilema species - M. gigas is also known as the cactus longhorn beetle.
Moneilema gigas normally feeds on chollas and prickly pear cacti, and is known to feed on saguaro seedlings. Larvae bore into cactus roots and stems, sometimes killing more susceptible individuals. Adults also feed on the surface of cacti. M. gigas are most active during mid or late summer - the adults typically emerging during the summer monsoon season.
Like many flightless beetles, these beetles have limited wing musculature with a rounded abdomen and thorax, similar in appearance to a number of other flightless desert beetles. Cactus longhorn beetles resemble and mimic the behavior of noxious stink beetles in the genus Eleodes.
