140 DIPTERA OP NORTH AMERICA. [PART IV. 



out cliscal cell, and with the anterior branch of the fourth vein 

 forked. This subdivision, according to my opinion, is not satis- 

 factonf. I possess a North American species (and European 

 species of the same kind may also occur) which has no discal cell, 

 but the posterior branch of the fourth vein of which is forked. 

 Such a species would neither be a Rhypholophus, nor a Dasyp- 

 tera. We might enlarge the character of Dasyptera and admit 

 in it all the species without a discal cell. But in the family of 

 Tipulidee we have abundant evidences of the fact, that the mere 

 presence or absence of the discal cell, if unsupported by other 

 characters, has but very little systematic value. Moreover, in the 

 genus Erioptera itself, we have the proof, that a discal cell may 

 be formed bj the forking of either the anterior or the posterior 

 branch of the fourth vein (compare in that genus the subgenera 

 Acyphona and Mesocyphona). Therefore, a subdivision based 

 upon the mere presence or absence of a discal cell would not be a 

 natural one. The comparison of the structure of the forceps of 

 the males, in connection with the venation and with the structure 

 of the antennae, would alone enable us to arrange the species of 

 the present genus in natural groups. Not having species enough 

 for such a distribution, nor having had an opportunity to study 

 the structure of the male forceps of many species, I am unable 

 to point out their natural affinities. As to an actual subdivision 

 in genera, I do not see any necessity for it at present ; in adopting 

 the two genera Ehypholophus and Erioptera, based upon the 

 nature of the pubescence of the wings, we have done enough, I 

 think, for any purpose of systematic distribution. 



The sti'uctural affinities between Rhyjiliolophus and Erioptera 

 are very great. Besides the difference in the nature of the pubes- 

 cence, I am not able to point out any character, peculiar to one 

 of these genera and foreign to the other ; this may be partly 

 owing to our as yet very imperfect knowledge of these genera. 

 The coloring of Bhypholophus is decidedly more dull than that 

 of Erioptera : gray and grayish-brown are the prevailing colors 

 in it. 



The generic name of Bhypholophus has been first proposed by 

 Kolenati for a single species, discovered by hira in Austria 

 (Wiener Entom. Ilonatschr. 18C0, p. 393). It was retained for 

 the same species by Dr. Schiner, in his Fauna Austriaca. In 

 the present work the definition of the genus has been enlarged, 



