AMERICAN DIPTERA. 249 



Illation of the apical field found in McjiidorJujnclius I do not know. 

 In general, the venation of Pafembolns difiers very little from that 

 of Trichophthalma ; so far as the structure of tlie wing goes, they 

 might very well belong to the same genus. 



B. — Proboscis long, directed downwards or backwards; subf. Rhynchocephalimr 

 {Living in N. America, etc.). 



KHYNCHOCEPHAL,i;S Fischer, ISOfJ. 



(1) Rhynchocephalus s. str. 

 Branches of cubitus meeting before margin of wing = second posterior cell 

 closed (Williston). 



Rliyuchoceplialiis sackeni Williston, Tr. Conn. .\cad. Sci., iv, p. 243. 

 As Williston's description is rather inaccessible, it is given here- 

 with : 



" Ulack, with light yellowish hair. Head broader than thorax, brownish- 

 black. Front broad, thin l.v blackish haired on tlie vertex; tlie lower part, tlie 

 face, cheeks, and posterior orbits, with thick, bushy, yellowish-white liair, 

 becoming nearly white below. Autenufe sliort, reddisii-yellow. base of first 

 joint infuscated, two first joints snbquadrate, third circular. Style of three 

 joints, first joint short, yellowish, second joint twice as long, ba.sal half infusca- 

 ted, third as long as two first, fuscous. Proboscis reaciiing the hind coxw, labium 

 black, other parts, with the slender minute palpi, luteous. Dorsum of thorax 

 and scutellum brownish-black, with yellowish hair; pleurie and pectus with 

 longer, bushy, grayish-white hair. Abdomen short and broad, black; second 

 segment above, and all the segments upon their sides, with yellowish hair. some- 

 what Intermixed with black at the incisures; third and remaining segments 

 above with sparse hairs and thick yellowish tomentnm, wanting upon tlieir 

 anterior borders, giving the abdomen a slightly fasciated appearance. Venter 

 with whitish pile. Lamellfe of the ovipositor slender, black, luteous at extreme 

 base, about as long as intermediate femora. Feet luteous. Femora white tomen- 

 tose, with tufts of hair on their undersides near thecoxse; anterior and middle 

 pairs, for their basal two-thirds, and posterior, except extreme tips, black. 

 Anterior and middle tarsi infuscated. posterior more so, blackish. Wings hya- 

 line; neuration as in the figure. 



"Adventitious oblique vein but slightly arcuated, terminating beyond the 

 middle of the apical half, not continued to jiosterior border, so that the third and 

 fifth posterior cells are not completely separated; both cross-veins obsolete. 

 Three submarginal cells; first and second open, slender. First posterior open, 

 second closed, the brief petiole terminating in the end of the costal vein before 

 the tip of the wing, fourth (third of Osten Sacken) closed, as usual ; third a little 

 shorter than fifth. Long. corp. 9min.; long. al. 9 mm. Oiympia. Washington 

 Territory, — H. K. Morrison." 



Dr. Williston adds that it closely resembles R. tanscheri, diHI'ring 

 chieflv in the length of the proboscis and the color of the head. 



TKANE. AM. ENT. 80C. XXXIV. (oJj AUGUST. 1908 



