l66 MAINE AGRICULTURAL EXPERIMENT STATION. I9IO. 



aa. Thorax or abdomen or both with considerable yellow. 



b. Hypopygium with two slender, slightly curved, dorsal 

 processes (fig. 147) ; fore metatarsus shorter than its 

 tibia, no coxal spur ; mesonotum vittate. 



6. Mycomya sp. 

 bb. Hypopygium not as described above, 

 c. Subcosta does not end in the costa. 



d. Subcosta ends in R^. i. littoralis. 



dd. Subcosta ends free. 



e. Dorsum of thorax black; posterior margin of the 



abdominal sclerites black. 2. ohtruncata. 



ee. Dorsum of thorax vittate ; margins of abdominal 



sclerites yellow. 3. sequax n. sp. 



cc. Subcosta ends in the costa. 



d. Posterior margin of tergites distinctly brown or 

 black ; anterior part yellow. 

 e. Petiole of media equal or longer than M,. 



f. Dorsum of thorax with distinct black mark- 

 ings ; fore metatarsus shorter than tibia ; 

 subcostal crossvein at the middle of the 

 cell Ri. 

 g. Mesonotum with 2 oblique lines which 

 meet at scutellum ; a median line and 2 

 elongate lateral spots over the base of 

 the wing. 7. ohliqiia. 



g^. Mesonotum with 3 confluent or subconflu- 

 ent dusky stripes. 8. tantilla. 



ff. Mesonotum with faint markings. 



9. nigracauda. 

 ee. Petiole of media shorter than Mo. 



f . Middle coxae without spurs ; fore metatarsus 

 shorter than its tibije; median vitta of tho- 

 rax usually paler than the laterals. 



10. hrevivittata. 



f f. Middle coxse with spurs ; fore metatarsus 



equal or longer than its tibia. 



g. Dorsum of abdomen with longitudinal 



black stripe ; fore metatarsus equal to 



tibia in length ; subcostal crossvein prox- 



imad of middle of cell Rj ; length 4.5 



mm.; hypopygium as figured (fig. 135). 



II. rnarginalis n. sp. 



