STUDIES ON THE HABITS AND DEVELOPMENT OF 
A HYMENOPTEROUS PARASITE, SPALANGIA 
MUSCIDARUM RICHARDSON 
‘C. H. RICHARDSON 
From the Entomological laboratory of the Bussey Institution, Harvard University 
SEVENTEEN FIGURES 
The present article contains the results of field and laboratory, 
investigations upon the life history of Spalangia muscidarum 
Richardson,! a hymenopterous parasite whose embryonic and 
larval life is spent within the puparium of the house fly, Musca 
domestica L. To this has been added a fairly complete résumé 
of the literature dealing with hypermetamorphosis in the order 
Hymenoptera and a consideration of the various larval types 
known to occur in hymenopterous insects possessing supernu- 
merary larval stages. 
The writer wishes to express his sincere gratitude to Dr. W. 
M. Wheeler and Mr. C. T. Brues for their aid and advice through- 
out the course of this work. 
Systematic relationships of the genus Spalangia. The genus 
Spalangia Latreille belongs to the Chalcidoid family Pteromalidae 
and is placed by Ashmead? in the subfamily Spalangiinae. ‘This 
subfamily is clearly distinguished by the oblong shape of the 
head, the antennae consisting of eight to twelve joints and in- 
serted close to the mouth, the long and depressed thorax, the 
distinctly petiolate abdomen and the length and narrowness of 
the costal cell of the fore wing. Of the four genera comprised 
in the subfamily Spalangiinae, the genus Spalangia is clearly sep- 
arated by a number of characters of which the following are 
1 Psyche, vol. 20, no. 1, 1913, pp. 38-39 (1 plate). 
? Classification of the chalcid-flies, or the superfamily Chalcidoidea. Memoirs 
Carnegie Mus., vol. 1, no. 4, 1904, p. 311. 
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