TACHYDROMIDAE. 31 



and CYRTOMA Meig. Mr. Walker records a N. A. species belong- 

 ing to the genus GLOMA Meig. 



FAM. XXX. TACHYDROMIDAE. 



Charact. The hindmost basal cell not always present, the second basal 

 cell sometimes coalescent with the discal cell ; when present they 

 are of a tolerable size, but the hindmost is always remote from the 

 border of the wing ; third longitudinal vein sometimes furcate ; an- 

 terior intercalary vein sometimes present, the posterior never. First 

 joint of the antennae very much shortened so that the antennae may 

 easily be taken for biarticulate. Empodium membranaceous and 

 of a linear form. 



To this family belong the genera: HEMERODROMIA Meig. with 

 CHYROMANTIS Rond. and MANTIPEZA Rond., PHYLLODROMIA Zett., 

 TACHYDROMIA Fair., DRYODROMIA Rond., ELAPHROPEZA Macq., 

 PLATYPALPUS Macq., PHOROXYPHA Rond., SCIODROMIA Hal. ( = 

 Microcera Zett.); ARDOPTERA Macq. (= Leptosceles Hal.), CLINO- 

 CERA Meig., with which HELEODROMIA Hal. (= Paramesia Macq.,) 

 and WIEDEMANNIA Zett. may be properly reunited. 



As genera occurring in N. A. I enumerate : HEMERODROMIA 

 Meig., TACHYDROMIA Fabr., PLATYPALPUS Macq., ARDOPTERA 

 Macq., and CLINOCERA Meig. If we may trust Mr. Walker's 

 statement, the genus DRAPETIS Meig. also occurs in N. A. 



Observation. With the Tachydromidse ends the series of those 

 families of Brachycera which in the greater development of their 

 basal cells differ from the following, and, with the exception of the 

 Lonchopteridse, form a rather natural series, if a linear arrangement 

 may be spoken of as a natural one. The peculiarities, which also 

 characterize this series of families, and any of which, combined 

 with that just mentioned, suffice to place a family under this head, 

 are the following: 1. the third joint of the antennae is composed 

 of a number of joints more or less soldered together ; 2. the third 

 longitudinal vein is furcate ; 3. one intercalary vein or both are 

 present; 4. the empodium is considerably developed. These pecu- 

 liarities characterizing the whole series of families hitherto spoken 

 of are much lessened in the Hybotidse and Empidse, and still more 

 so in the Tachydromidx. Txniaptera, Dacus and other genera 

 with the third basal cell more developed, are placed by most of 

 the authors lower down in the series of families which follow. In 



