RHYPHIDAE XYLOPHAGIDAE. 15 



TRIA Meig., CRAPITULA Gimm., PLECIA Wied., EUPEITENUS Macq., 

 PACHYNEURA Zett., and SPODIUS Loew. 



Species of the genera SCATOPSE, ARTHRIA, DILOPHUS, BIBIO, 

 PLECIA, and EUPEITENUS are known to occur in N. A. 



Note. At the time when this was written by Mr. Loew, neither he nor I 

 possessed specimens of the genus Hesperinus, which its author, Mr. Walker, 

 referred to the TipuJidse. Having obtained specimens since, collected by 

 Mr. R. Kennicott near the Great Slave Lake, I found that Hesperinus be- 

 longs to the Bibionidx, and is apparently synonymous with Spodius Loew. 

 Accordingly, Hesperinus Walk, is to be added to the genera of this family 

 occurring in N. A., and stricken out from among the Tipulidx. 0. S. 



FAM. X. RHYPHIDAE. 



Charact. Ocelli three. Thorax without transverse suture ; wings with a 

 perfect discal cell ; empodium similar to a pulvillus ; pulvilli want- 

 ing. 



Of this family also a single genus, RHYPHUS Meig., is known, 

 which has representatives in Europa, Asia, and N. A. 



Observation. There is a genus Epidapus Hal., remarkable for 

 having no wings and no poisers, which I have omitted in the pre- 

 ceding enumeration of families, because I do not know it. It is 

 quite impossible to place it among the Mycetophilida, as Walker 

 does, if we characterize the families as we have done. It rather 

 seems to find its place among the Cecidomyidce ; but there is nothing 

 decisive to be said without the examination of fresh specimens. 



II. BRACHYCERA. 



FAM. XI. XYLOPHAGIDAE. 



Charact. The three basal cells very prolonged, the third longitudinal vein 

 furcate ; both intercalary veins always present ; the marginal vein 

 encompassing the whole wing ; the third joint of the antennae annu- 

 lated or divided into separate joints, always without style or termi- 

 nal bristle. Tibiae with spurs ; the empodium very developed and 

 pulvilliform. 



The genera belonging here are: XYLOPHAGUS Meig., PACHY- 

 STOMUS Latr., SUBULA Meig., ELECTRA Loew, CHRYSOTHEMIS 



