BY ROWLAND E. TURNER. 71 



I have been compelled to use the mouth-parts to a considerable 

 extent in the subdivision of the genus, although I am aware of 

 the inconvenience entailed owing to the difficulty of study with- 

 out dissection, which cannot always be resorted to. But I have 

 found that the characters used by Ashmead, the hypopygium 

 and clypeus are far too variable to be any guide except for specific 

 distinctions. I have thought it best to sink Thynnoides, though 

 the structure of the anterior coxae in the male and the pygidium 

 and maxillary palpi (3-jointed) of the female may warrant its 

 retention when more material is available. 



Table of Subgenera of the Genus Thynnus Fab. 



i. J\ Labrum strongly narrowed posteriorly. 



A. Joints of the antennae strongly arcuate beneath. 



a. Second recurrent nervure received by the third cubital cell 



at some distance from the base. Hypopygium prominent, 

 not emarginate. 

 ( $ . Second abdominal segment rugose, with a transverse 

 carina at the base and at the apex. Pygidium simple). 



Phymatothynnus. 



b. Second recurrent nervure received very near the base of the 



third cubital cell. Hypopygium short and emarginate. 

 ( $ . Second abdominal segment with one carina or more. 

 Pygidium simple. Thorax very coarsely sculptured). 



Psammothynnus Ashm. 



B. Joints of the antennae not strongly arcuate beneath. 



a. Second recurrent nervure received by the third cubital cell 



at some distance from the base. 

 a 2 . Abdomen flattened, the segments not constricted. 



a 3 . The three apical joints of the maxillary palpi elongate. 



Zeleboria Sauss. 

 b 3 . The joints of the maxillary palpi slender and subequal. 



Glaphyrothynnus. 

 b-. Abdomen not much flattened, the mouth-parts variable. 



Lophocheilus Gu£r. 



b. Second recurrent nervure received close to the base of the 



third cubital cell. 

 a 2 . Apical joint of the maxillary palpi rudimentary. 



Catocheilus Guer. 

 6 3 . Apical joint of the maxillary palpi normal. 



a 3 . Labium strongly bilobed. Agriomyia Gue'r. 



