156 C. It. Osten Sacken: 



bodies : characters which, in the european J>. sylvicola, are connected 

 with its habit of flying in zig-zag, Ephemera-M^Q, in sbady localities. 

 Long appendages, wbether antennae, legs, or caudal setae enable in- 

 sects to regulate their fligbt, during such evolutions. Besides the 

 european Dolichopeza, several north -american species of the same 

 group, which I have had occasion to observe, share this habit of 

 zig-zag flying on the same spot; among them is the Tipula dispellens 

 "Walk, for which I introduce the new genus Brachypremna. I have 

 but little doubt that the tropical Megistocerae indulge in the same 

 exercise. 



The antennae of the male, in this group, are often much longer 

 than those of the female; sometimes of extraordinary length. But 

 that this character is, generically, an unimportant one, is proved by 

 the genus Megistocera, where exceedingly long antennae will occur 

 in some species, and exceedingly short ones in others, without any 

 note-worthy difference in the rest of the Organization. 



The structure of the palpi, the spurs at the tip of the tibiae 

 (usually present, although sometimes exceedingly minute) the arrange- 

 ment of the veins round the stigma and the discal cell etc., prove 

 that the genera in question are Tipuli dae longi palpi. I am not 

 able to characterize the group ofDolichopezinae as a whole in 

 a satisfactory manner; besides the great length and slenderness of 

 the legs , the anterior brauch of the second vein may be used for 

 that purpose: it is either altogether absent (Dolichopeza), or obsolete, 

 or eise perpendicular, and not as usual oblique, thus rendering the 

 rhomboid cell near the stigma more or less Square. 



The genera may be grouped as follows: 



Antennae 13-jointed; male forceps of a complex structure 



Dolichopeza, Scamboneura, Apeilesis. 

 Antennae with less than 13 joints; male forceps small, of a simple 

 structure. 

 Wings crystalline; fifth posterior cell not in contact with the 



discal. Megistocera. 



Wings not crystalline; fifth posterior cell in contact with the 

 discal. 

 Head on a necklike Prolongation ofthethorax; seventh vein 

 Short, running into the anal angle. Brachypremna. 

 Head more closely applied to the thorax; the seventh vein 

 reaches the margin some distance from the anal angle. 



Tanypremna. 



