ABTll. NOTES ON NEARCTIC BIBIONID FLIES McATEE. 21 



DILOPHUS ORBATUS Osten Sacken. 



D. [ilophus^ oriatus Osten Sacken (C. R.), in LeConte's edition of The 

 Complete Writings of Thomas Say on the Entomology of North America, 

 vol. 2, 1859, p. 70 [Florida]. 



In the paper of 1823 in which Say's other species of Dilophus 

 and Bihio were described (to which several references are made in 

 the present article) he proposed a species Bihio orhatus.^^ Later 

 authors (Wiedemann, 1828, Bellardi, 1859, and Osten Sacken, 1859) 

 have used the name orhatus in the genus Dilophus^ in each case prob- 

 ably for a different species. 



Say was perfectly aware of the characters distinguishing Bibio 

 from Dilophus^ and it has not been found necessary to shift any 

 other of his species as between these two genera. I fail, therefore, 

 to see the point of rejecting Say's assignment of orhatus to the genus 

 BiMo and accepting that to Dilophus by Wiedemann. While Osten 

 Sacken says "Wiedemann . . . had specimens communicated by Say 

 before him," there is no definite evidence that such was the case. 

 Wiedemann did not have specimens of all of Say's species and his 

 usual remark when he had seen specimens, "In meiner Sammlung," 

 is lacking in this instance. Even had such specimens been available 

 to Wiedemann, the chances of transposition or error in labels are 

 such that we could by no means accept Wiedemann's reference of 

 orhatus to Dilophus when Say certainly was just as well informed 

 as he with respect to the generic characters. Wiedemann's action is 

 best regarded as a misidentification and the name Dilophus orhatus 

 Wiedemann as a synonym of Bihio orhatus Say. 



Wiedemann's action therefore does not preoccupy the combination 

 Dilophus orhatus and the next description under this combination, 

 undoubtedly referring to a Dilophus^ should be recognized. This 

 combination is present in the contribution of Osten Sacken, cited at 

 the beginning of this discussion, and in the first installment of 

 Bellardi's "Saggio di Ditterologia Messicana," both published in 

 1859. So far I have found no means of deciding as to priority 

 between these works, but since Osten Sacken's name undoubtedly 

 refers to the Nearctic form it is selected for use in the present con- 

 nection. 



Male. — Head, body, and legs brownish to black, mostly shining, 

 with black hairs; genital segment with a broad cleft about half its 

 length, superior plate half as long as wide moderately convex pos- 

 teriorly; wing sordid-hyaline, yellowish near costa where the veins 

 and stigma are pale fuscous. 



Female. — Same description applies except as to genitalia and 

 wings ; latter dusky to blackish, veins darker costally, stigma large, 

 but little darker than surrounding membrane. 



Length of wing, 3.5-5.5 mm. 



"Compl. Writings, vol. 2, 1859, pp. 69-70 [Pennsylvania]. 

 313&— 22— Proc.N.M. Vol .60 28 



