Note on the Number of Spiracles in Mature Chalcid Larvæ

Abstract

During a recent trip to Washington, D. C., while discussing the life history of Prospaltella perniciosi Tower a chalcid parasitic on the San Jose Scale, Aspidiotus perniciosus Comst., with Mr. J. C. Crawford of the National Museum, he called my attention to a translation of a Russian work published in 1912 entitled, Parasitic and Hyperparasitic Insects, by Iv Chewyreuv, and in particular to a statement made by the author on page 16, which is quoted in full: “In the same paper the author named gave (25, 35) a much enlarged drawing of Dibrachys boucheanus Rtzb. This figure shows not a single spiracle, as if the larva has not got them. While as a matter of fact it does have them, and under the magnification it was drawn, they must be quite evident; nothing is said about spiracles in the description either. The fact is that the arrangement of spiracles in mature chalcid larvae is very peculiar and as will be shown later, makes it possible to recognize them at once and to distinguish them from the larvae of allied families. They have nine pairs of spiracles, two of which are on the meso- and metathorax and the rest on the first seven abdominal segments; hence, there are no spiracles on the prothorax and last two abdominal segments. This is the peculiarity Howard did not bring out in his drawing which is therefore incorrect.”