Severe injury to the roots of cucumber plants has occurred since January of this year (1922) through the attacks of the larvae of certain minute “fungus-gnats” belonging to the family Sciaridae. Although such attacks have not been recorded previously by growers of cucumbers, it is more than probable that the flies have been present in glass-houses for a number of years, and that damage arising through their agency has mistakenly been attributed to “eel-worms.”