Libelloides coccajus, the "owly sulphur", is an owlfly species belonging to the family Ascalaphidae, subfamily Ascalaphinae.

This rare insect is present in France, Czech Republic, Germany, Italy, Spain and Switzerland.

[2] These owlflies mainly inhabit areas with tall grass and sunny rocky slopes, at an elevation up to 1,500 metres (4,900 ft) above sea level.

The wings do not have scales and are partly transparent, with bright yellow areas in the first third, dark brown on the external side.

[3] The Libelloides italicus type in the University of Copenhagen Zoological Museum, does not correspond to any endemic species of Ascalaphidae living exclusively in the Italian peninsula and it is now considered to be a junior synonym of Libelloides coccajus.