. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. THE SORGHUM MIDGE. 57 and the predominant parasite is not found, these parasites may be seen actively ovipositing through the outer glume of the sorghum seed in precisely the same manner as has been described with reference to Apros- tocetus diplosidis. At the same time the writer has reared this para- site from Setaria glauca infested by another species of midge. The pupae of Aprostocetus diplosidis and Tetrastichus sp. are found occupying the same position within the sorghum seed as is taken by the pupae of the
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. THE SORGHUM MIDGE. 57 and the predominant parasite is not found, these parasites may be seen actively ovipositing through the outer glume of the sorghum seed in precisely the same manner as has been described with reference to Apros- tocetus diplosidis. At the same time the writer has reared this para- site from Setaria glauca infested by another species of midge. The pupae of Aprostocetus diplosidis and Tetrastichus sp. are found occupying the same position within the sorghum seed as is taken by the pupae of the sorghum midge, viz, directly against the ovary within the delicate palet, the head directed toward the apex of the seed. These pupae are not enveloped in the larval skin of the midge, but are naked. While microscopic examinations of sectioned midge larvae have not been made for the purpose of studying the develop- ment of these parasites, it is evident that these parasites oviposit within midge larvae in all stages of de- velopment. Ex- amination of seed observed to have been visited by parasites has re- vealed, in some instances, newly -, . , , , Fig. 31.— Tetrastichus sp.: Female. Greatly enlarged. (Original.) hatched larvae, while in other cases half-grown or even full-grown larvae were present. PREDACEOUS ENEMIES. By far the most important predaceous enemy of the midge is the Argentine ant (Iridomyrmex Jiumilis Mayr) occurring in Louisiana. These ants swarm over the sorghum stalks and heads in the fields and whenever they find midge pupae projecting from the apex of the seed they seize the latter in their mandibles and carry them off to their nests. The fly Psilopodinus jlaviceps Aldrich has been observed by the writer to prey upon the adults of the midge. These flies rest upon a sorghum blade conveniently near a head and dart out frequently, seizing an adult and devouring it immediately. On July 15 the writer saw a hummingbird (probably Trochilus alexandri, according to
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