NOTE ON THE NUMBER OF SPIRACLES IN MATURE 
CHALCID LARVZE. 
By DANIEL G. Tower, M. Sc., 
Lafayette, Ind. 
During a recent trip to Washington, D. C., while discussing 
the life history of Prospaltella perniciost Tower a chalcid para- 
sitic 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 bouch- 
eanus 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 larve is very peculiar and as will be shown later, makes 
it possible to recognize them at once and to distinguish them 
from the larve 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 seg- 
ments. This is the peculiarity Howard did not bring out in 
his drawing which is therefore incorrect.”’ 
The statement made in the above quotation that all mature. 
chalcid larve have nine pairs of spiracles does not hold true in 
the case of Prospaltella perniciosi, for the adult larva of this 
chalcid has only eight pairs of spiracles, two pairs of which are. 
thoracic and six pairs abdominal. 
In tracing the tracheal system of this scale parasite through 
its two larval forms, one finds the tracheal system to consist in 
the first larval stage of two longitudinal main trunks lying near- 
the surface, one on either side, each bearing ten short, stub-like 
*(25, 35) refers in the author’s bibliography to Dr. L. O. Howard’s paper, ‘‘A 
Study res Gk Parasitism’’—U. S. Dept. Agri., Div. Ent. Techn. Ser. No. 5,. 
p. 35, 1897. 
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