24 PROCEEDINGS OF THE NATIONAL MUSEUM vol.69 



This is the largest and probably the most important of our genera 

 of Braconinae. Unfortunately nothing is known regarding the host 

 relationships of most of our species. A few of them, however, have 

 been rather commonly reared ; and wherever authentic host records 

 are available these will be mentioned. in the discussions of the various 

 species. 



KEY TO THE SPECIES OF BASSUS. 



Bassus rugareolatus Viereck, B. quehecensis (Provancher) , and B. 

 verticalis (Cresson) are not included in this key. See discussion of 

 these species in the text. 



1. Frontal impressions margined by carinae; first abdominal tergite with a 



median longitudinal elevation, usually in the form of a polished keel, 

 arising at the posterior margin of the basal impression and extending 

 posteriorly; scutellum more or less distinctly carinately margined at apex; 

 head not, or only slightly, excavated behind; third segment of labial 

 palpi very short, sometimes scarcely apparent; antennae normally 38 to 

 50 segmented; second cubital cell large, triangular, generally sessile; 

 second abscissa of medieUa much longer than the first; large species, 



usually measuring 7 to 9 mm. in length 2. 



Frontal impressions immargined; otherwise not combining all the above 

 characters 7. 



2. Thorax, except usually the metapleura and propodeum, black; mesonotum 



always black 6. 



Thorax testaceous or ferruginous, at most with the prothorax, the pectus 

 and the sutures surrounding the scutellum black; mesonotum never 

 black 3. 



3. Anterior and middle legs entirely testaceous — 1. marginatifrons, new species. 

 Anterior and middle legs mostly black 4. 



4. Inner spur of posterior tibia not half as long as the basitarsus; propodeum 



weakly sculptured, with lateral longitudinal carinae and two weak, nearly 

 parallel median longitudinal carinae, not areolated; ovipositor sheaths 



considerably longer than the body 5. 



Inner spur of posterior tibia half as long as the basitarsus; propodeum 

 completely areolated, the separating carinae very prominent, the areas 

 rugose within; metapleura rugoso-reticulate; first abdominal tergite 

 rugose on either side of the prominent median longitudinal keel 



2. floridanus, new species. 



5. First abdominal tergite smooth, the basal impression not completely margined 



by carinae, and the median elevation behind the impression poorly defined, 

 not developed into a sharp keel; furrow in front of scutellum not distinctly 

 pitted; inner spur of posterior tibia only slightly less than half the 



basitarsus 3. nigrotrochantericus (Viereck) . 



First abdominal tergite with the basal impression completely margined by 

 strong carinae, which unite behind the impression to form a sharp promi- 

 nent median ridge; furrow in front of scutellum with several pits; inner 

 spur of hind tibia much shorter than half the basitarsus 



4. imitatus (Cresson). 

 0. Inner spur of of middle tibia much longer than half the middle basitarsus; 

 inner spur of posterior tibia at least half as long as the posterior basi- 

 tarsus; scutellum strongly margined at apex; ovipositor sheaths only a 

 little longer than the abdomen 5. texanus (Cresson). 



