NOV. 4, 1923 GAHAN: CHALCIDOID PARASITE 409 
nated the holotype of the species, this seeming necessary because there appears 
to the writer to be a possibility that Mayr has wrongly associated the sexes. 
The genera of Pteromalidae are at present in a chaotic condition making it 
practically impossible, in many instances, to place a species satisfactorily. 
Peridesmia may be truly a synonym of Trichomalus as Mayr considered it. 
Nevertheless the presence in the male of a perfectly smooth area extending 
from the base of the mandible upward along the posterior eye-margin nearly 
or quite to the top of the eye, makes the genus readily recognizable in the one 
sex, at least, and for that reason the name Peridesmia is resurrected from the 
synonymy to cover the species aqguisgranensis Mayr and the new species 
described herewith, which are the only two species in which the character is 
known to occur. 
No specimens of the genotype species have been seen by the writer. Ihe 
generic diagnosis here given is, therefore, drawn from the new species. The 
characters given by Mayr for both sexes of aquisgranensis agree with this 
diagnosis, in so far as they go, except that the propodeum is said to have a 
large neck. ‘The new species is practically without a neck on the propodeum 
in either sex. 
The description of the male of aquisgranensis agrees so closely with the 
male of the new species that there can be no doubt that the two are closely 
related, and the smooth area on the cheek and posterior orbit is such an 
unusual character in Pteromalidae that I find it difficult to believe that it 
would occur in two species which differed otherwise by having a large neck 
on the propodeum in the one case and practically no neck at all in the other. 
Mayr apparently associated the females with the males on the basis of col- 
lected specimens which he found in the Foerster collection pinned with the 
males but which Foerster seems to have refrained from sending to his corre- 
spondents under the name, perhaps because of a doubt as to the correctness of 
the association. I am of the opinion that. Mayr may have drawn his descrip- 
tion of the propodeum from a female which was wrongly associated with the 
male and that the male may be found to lack the neck on the propodeum. 
Only an examination of Mayr’s types can settle this point. 
Generic description—Head strongly transverse, wider than the thorax and 
thin antero-posteriorly; eyes not hairy; occiput concave and immargined; 
antennae 13-jointed, inserted near middle of head; scape slender, pedicel 
longer than the first funicle joint, two ring-joints transverse, funicle 6-jointed, 
club 3-jointed; mandibles both 4-toothed; maxillary palpi 4-jointed; labial 
palpi 2-jointed; head of the male somewhat thicker antero-posteriorly than in 
the female, the cheeks slightly swollen with a perfectly smooth area extending 
from the base of the mandible upward along the posterior eye-margin nearly 
or quite to the top of the eye; female without such a smooth area; pronotum 
strongly transverse, perpendicularly truncate in front, the truncature not 
distinctly margined above, mesoscutum distinctly broader than long, the pa- 
rapsidal grooves very delicate but traceable for the whole length of meso- 
scutum; axillae broadly separated; scutellum about as long as mesoscutum and 
slightly flattened dorsally; propodeum without a neck, punctate, with well 
