326 Annals Entomological Society of America [Vol. IX, 



Abdomen shining black, hypopj-gium prominent. 



Wings brownish on anterior margin, especially in costal cell. Costal 

 index about 1.9, 4th vein index about 2.6, 5x index about 2.0, 4c index 

 about 0.0. 



Length of body 2^'4mm., wings 2>^mm. 



Type and 7 paratypes, collected at Potlatch, Ida., Sept. 9, 

 1912, on the windows of a sawmill (J. M. Aldrich). Also one 

 specimen, Yale, Ida., Sept. 10, 1912 (Aldrich). The type and 

 5 paratypes have been returned to Prof. Aldrich. 



Scaptomyza Hardy, 1849. Proc. Berwicksh. Nat. Club, 349. 



This genus is easily recognized, in our American species, 

 by the 2 or 4 acrostichal rows. The larvae are not exclusively 

 leaf miners, as I have bred 5. adusta Lw. and S. graminum Fall, 

 through several generations on tomato fruits and also on 

 potato tubers. 



Our species have been separated largely on the basis of the 

 thoracic color and the presence or absence of the spot at the 

 tip of the wings. Both characters are extremely unreliable, 

 however, as neither the dark thorax nor the wing spot appears 

 until a day or two after the adult emerges. The genus is 

 easily divided into two groups on the basis of the number of 

 rows of acrostichal hairs. 5. adusta Lw. and S. terminalis Lw. 

 have 4; S. graminum Fall, has 2. 



S. flaveola Meig. probably does not occur in North America. 

 Most specimens so labelled seem to be immature specimens of 

 the three above named species. S. vittata Coq. 1895 Proc. 

 Acad. Nat. Sci. Phila. 318, is perhaps a synonym of S. graminum 

 Fall. Geomyz. 8. I have been unable to find the type specimen 

 of vittata. There are some tropical species belonging to the 

 two-rowed group, but I have not described them because of my 

 uncertainty as to m.ost of this genus. 



S. apicata Thorns. 1868, Eug. Resa. 597, is probably a synonym 

 of 5. terminalis Lw. 1863, Berl. Ent. Zt. I have examined a 

 very large series of this form from the Pacific Coast and from 

 Canada and New England, including Loew's specimen. It is 

 extremely variable in several characters (size, color, wing- 

 markings) and there may well be several species involved. 

 Some specimens are practically indistinguishable from S. 

 adusta Lw. ; but that species is not especially variable, and is 



