225 



Larva (PI. XXXV, Fig. 2). — Length, 19 mm. White, or faintly 

 tinged with yellowish. 



Head large for the family. (No structural description given hy 

 Needham.) On the ventral side of the three thoracic segments is a 

 pair of minute brownish points. Ventral side of segments 2-7 each 

 with a single median proleg — a mere soft, white, transversely placed 

 ridge, without hooks or claws. The abdomen is without other tuber- 

 cles, spines, or hairs. Spiracles large, widely separated. Spiracular 

 disc with 4 thick marginal processes, the upper pair blunt apically, 

 fringed with hairs, and separated by the full width of disc, the lower 

 pair a little more pointed and a little closer together ( PI. XXXV, Fig. 

 3). Anal blood-gills slender, 4 in number. 



Pupa (PI. XXXV, Fig. 9). — Length, 12 mm. Ventral view and 

 general appearance as in figure. Apical carina on each abdominal 

 segment fringed with short stiff hairs, those on the ventral side of 

 eighth segment more comb-like, and interrupted on the median line in 

 female. 



The foregoing descriptions are abridged from Needham's paper, 

 and the accompanying figures are copied from the same author. 



The materials used by Needham in making his descriptions were 

 obtained at Lake Forest, 111., where the larvae were found boring in 

 the dead stems of buttonbush and willow lying on the mud at the 

 borders of shallow pools. 



The species is represented in our Laboratory collection by imagines 

 from Algonquin and Urbana, 111., and from Philadelphia. Pa., all be- 

 ing taken in June. 



UiyA Haliday 



GENERIC CHARACTERS 



Larva. — Body cylindrical, without hairs ; pseudopods faintly in- 

 dicated in the form of slight transverse ventral fusiform areas on 

 apical portion of abdomen. Labium entire ; maxillary palpi longer 

 than the rather stout antennae. Apical abdominal segment with 5 

 processes on margin of spiracular disc. 



Pupa. — General appearance similar to that of Limnophila, but the 

 armature of the abdomen differs noticeably in being confined to the 

 posterior margins of the median dorsal segments. 



Uea eeEGans Osten Sacken 



TJla elegans Osten Sacken. Mon. N. Am. Dipt., Vol. 4, p. 276. Imago. (1869) 

 Ula elegans Osten Sacken, Alexander, Pomona Jour. Ent. and ZooL. Vol. 7, pp. 

 1-8. (1915) 



