124 PSYCHE [December 
Host Relations of the Genus. 
Heretofore, nothing has been recorded concerning the hosts of this genus. 
Beyond, we give a record of a large series of rearings of the type species, all of which 
may be included in the following general statement: ‘The genus attacks gregariously 
or “socially ” the puparia of three or four genera of the higher Diptera — Chrysomyia 
(macellaria), Lucilia, Musca (domestica), Sarcophaga and Phormia (regina); also it 
may be found to attack Calliphora. Allof these are forms of economic importance. 
In nature, the genus attacks mostly Chrysomyia (macellaria) and Phormia (regina), 
so far as is known. In confinement, it readily attacked the puparia of Cynomyia 
cadaverina Desvoidy, in addition to the others. Though gregarious, it is an external 
parasite, the larvae not penetrating the host’s body. 
Distribution of the Genus. 
This genus appears to be very abundant, at least in the state of Illinois. It has 
not however been recorded from more than two localities in that state, namely Algon- 
quin (Nason, 1906) where it was first discovered and Urbana and Champaign, two 
adjoining towns farther south in the state. 
The Type Species of the Genus. 
Nasonia brevicornis Ashmead, as previously stated, has never been described, 
merely being named in parentheses as type of the genus. Other than that, it has 
been mentioned but once in the literature, namely by Nason (1906), who records its 
first collection. Heretofore, its status has been that of a nomen nudum, or nearly. 
1. Nasonia brevicornis Ashmead, species nova. 
Ashmead, 1904, pp. 317-318. 
Nason, 1906, p. 156. 
Normal position. 
Female: Wength, very variable; maximum, 2.30 mm.; minimum, 1.0 mm.; 
range, 1.8 mm.; average, 1.75 mm.; mode, 2.0mm. Usually stout. 
General color metallic dark brassy green, the abdomen dark, less metallic, shin- 
ing, the metathorax dull; scape and pedicel fuscous, the latter often much darker, 
especially dorsad; flagellum neutral blackish, dusky; legs fuscous with the follow- 
ing exceptions — coxae concolorous, metallic, the intermediate ones often fulvous 
at the apex or the entire joint dull blackish; apical tarsal joints dusky; most of the 
dorsal aspect of the caudal femora blackish. Eyes garnet; ocelli pinkish; tegulae 
