The Habits of Pheidole Ridicula Wheeler , With Remarks on Habit Patterns in the Genus Pheidole (Hymenoptera: Formicidae)

During I965 the writer was able to study seven colonies of Ph. ridicula at La Feria, Texas. The observations in this paper were made on these colonies or on individuals transferred from them to observation nests. There are .(ew North American ants as poorly known as Ph. ridicula. When W. M. Wheeler described this species in I916 he had seen three specinens, all majors (I). One of these (the type) was taken by C. L. Scott at Brownsville, Texas. The other two, in the collection of the U. S. National Museum, came from San Diego, Texas, a town about 14o miles northwest of Brownsville. Except for these locality records no field data for ridicula were available and, as far as can be determined, no additional records have been published for this .species. The nests of ridicula are surprisingly difficult to find and this seems to be the reason why the species, which is a. door-yard ant in the lower Rio Grande Valley, has escaped observation for the past fifty years. To judge from the La Feria colonies, ridicula prefers to nest in areas where there is a heavy cover of weeds, often nettles, common sunflower, Johnson grass and careless weed. These weeds not only conceal the nests but also the foragers which come from them. During December 1964 I made repeated visits to an area where there were two flourishing colonies of ridicula. It is now apparent that I often stood directly above these nests but neither was discovered until the covering weeds were removed. There are other features which make the nests of ridicula hard to find. A mature colony of this ant contains at least seventy-five majors and three