170 XKW YOltK STATK MISKUM 



the next small, the followiug ones again, slender and elongate, 

 the last one small; these are all only thinly haired (flg.3). The 

 eyes ronnd, bare, the ocelli wanting (or rudimentary?) ; front 

 broad. The arching of the thorax gradually becomes greater 

 from the head backward, the transverse suture wanting; scutel- 

 lum short but wide; metathorax moderately large. Abdomen 

 8-jointed, hypopyginm somewhat projecting. Legs long; coxae 

 not elongated; the fore femora shortest, the posterior pair long- 

 est; tibiae without spurs; tarsii of the posterior pair of legs ex- 

 tremely slender, and at least as long as the femora and tibiae 

 taken together, the metatarsus about twice as long as the follow- 

 ing joints taken together, ajtical joints small, the sole of the clawed 

 joint bristly, the claws quite long and bent; the halteres promi- 

 nent. \yings long and narrow ; venation as shown in figs. 1 and 2. 

 The first figure is from Y. d. Wulp (1S77) the second after Meigen 

 (1818). No North American species have been descrilied. 



Genus 31. Hydrobaenus Fries 



Veteusk. Akad. Hancll., 1829. 176. 1830 

 Psiloeerus Ruthe, Isis. XI. 1207. 1831 

 (PI.34, figs. 2 to 11) 

 Fries (1830) describes the larva and pupa at considerable length 

 and gives figures illustrating details of each ; the latter are repro- 

 duced on })l.o4, figs. 2 to 5 and 8. 



Larva. The lana is described as being 4 mm. in length, green- 

 ish in color, quite slender, and cylindrical. The head (fig.2) is 

 small, obcordate and black. The antennae are three-jointed. On 

 the ventral side of the first thoracic segment is a pair of feet with 

 setae (fig.o). On the dorsal surface of the eleventh abdominal 

 segment are two cylindi-ical ju'ocesses, the extremity of each with 

 a tnft of long hairs. On the ventral surface of this segment are 

 the blood .gills, two in numbei* and shorter than in C h i r o n o- 

 m u s. The twelfth segment has the usual anal feet and four blood 

 gills, the latter, however, diftering from C h i r o n o m u s in hav- 

 ing at the apex of each a little tuft of hairs. 



Pupa. (Figs, n and 8) Thorax with short and narrow respira- 

 tory tubes. Tlie caudal end is jn'ovided with two tufts of long 

 hairs. The species slu>wn by Fries is H. lugubris, an 

 European sjiecies. 



Imago. Very small black sjiecies, the males as well as the 

 females of wliicli have the aniennac^ with short hairs. Head small, 



