Z PROCEEDINGS OF THE NATIONAL MUSEUM Vol.80 



The type species of the genus Hylotomomyia is Admontia hyloto- 

 mae Coquillett, by original designation. The genus was said to 

 differ from Spathitneigenia in having no spines on the fourth seg- 

 ment of the ventral abdominal keel of the female. This is evidently 

 of merely specific importance, and Curran combined the two genera 

 in his revision cited above. 



The genus is one of the easiest to recognize, from the presence 

 on the lower part of the parafacial of an area bearing distinct hairs. 

 The female has the abdomen keeled below and bearing stubby spines 

 on the ventral margin of the keel, at least on the third segment. This 

 female character is shared with Lydella and several other genera, 

 which all have bare parafacials. 



The genotype has the following additional characters among 

 others : Hypopleural bristles and postscutellum present ; one vertical 

 bristle in male and female; ocellars proclinate; two upper frontals 

 reclinate, the second i^air largest ; frontals extending to tip of second 

 antennal joint; front slightly prominent at antennae, the face dis- 

 tinctly receding; facial ridges with several bristles above vibrissae, 

 the latter at oral margin, which is considerably above the lower edge 

 of the head behind ; palpi and proboscis of ordinary form, the latter 

 short; antennae extending about three-fourths of the way to the 

 vibrissae, third joint about twice the second, at tip projecting 

 slightly forward (not nearly so much as in Acemyia) ; arista bare. 

 Acrostichal bristles, 3, 3 (one pair just before suture) ; dorsocentral, 

 3, 3; presutural, 2 (inner small) ; supraalar, 3; intraalar, 3; sterno- 

 pieural, 2, 1 ; pteropleural small ; inf rasquamal setules absent ; scutel- 

 lum with three lateral pairs and one small discal, the apicals small 

 and upturned. First abdominal segment with a pair of median mar- 

 ginals, second to fourth with cliscals and marginals, the discals much 

 better developed in male than female, the former having three irregu- 

 lar pairs of different sizes, the latter with usually one small pair. 

 Apical cell ending a little before tip of wing, bend of fourth vein 

 rounded and oblique; hind cross vein in normal position, joining 

 fourth vein at three-fifths of the distance between small and bend. 



The genus has a considerable degree of economic importance, and 

 has been reared without exception from sawflies; many rearings are 

 cited under the respective species. Several of the species, however, 

 have not yet been reared. 



Eleven species are now known. I have seen the types of all, and 

 with the exception of two they were before me in the preparation of 

 the present paper. 



