THE CANADIAN ENTOMOLOGIST, 269 



NOTES ON THE NORTH AMERICAN SPECIES OFISODONTIA, 



PATTON, WITH DESCRIPTIONS OF A NEW 



SPECIES AND VARIETY. 



BY H. T. FERNALD, PH. T>., AMHERST, MASS. 



The North American species of Isodontia may be distinguished by 

 means of the following table : 



1. Mandible with two teeth (anterior tooth sometimes partly divided) . . 2 

 Mandible with three teeth 7 



2. Petiole black 3 



Petiole yellow exornata, n. sp 



3. Third segment of antenna longer than seventh or eighth 4 



Third segment of antenna shorter than seventh or eighth 5 



4. Median segment above with long white 



hairs macrocephala^ var. cinerea, n. var 



Median segment above without long white hairs . . .macrocephala, Fox 



5. Body hairs gray 6 



Body hairs black azteca, Sauss., var 



6. Front part of wings fuscous azteca, Sauss 



Wings entirely fuscous azteca, Sauss., var 



7. Legs more or less yellowish 8 



Legs black apicalis, Sm 



8. Abdomen black tibialis, Lep 



Abdomen more or less yellowish elegans, Sm 



I atn hardly prepared at present to accept Isodontia elegans^ Smith. 

 as a variety of /. apica/is, Smith. The differences between the two seem 

 to be very constant, and their distribution appears to be somewhat differ- 

 ent, elegans being more a southern and western form, v^\\\\q apical is occurs 

 chiefly in the central, eastern and northern States. 



Pation (Proc. Ent. Soc, Wash., III., p. 46) regards fuacrocephala, 

 Fox, as a synonym of azteca, Sauss. With this I am unable to agree, all 

 the specimens of a large series of both of these species before tne being 

 distinguishable almost at a glance. The type specimen of macrocephala 

 has the anterior tooth of the mandible v/ith a groove dividing it into two 

 portions, which leads me to believe that in this insect the mandible was 

 originally three-toothed, but that the anterior two have partially fused. 

 All my specimens of azteca, on the other hand, indicate an originally two- 

 toothed mandible, and though the anterior tooth is blunt in many cases, it 



