306 



and in order to make this study as comprehensive as possible I give 

 here a brief description of the species. 



Subfamily TRICHOCERINAE 

 Trichockra sp. ? 



Larva. — Length, lo mm. Pale testaceous. 



Head complete, similar to that of the Alaskan species described 

 under the above subfamily name on a previous page of this paper. 

 Prothoracic spiracle small, surrounded by a pale ring ; anterior third 

 of prothorax paler than posterior two thirds ; each thoracic segment 

 with a transverse linear depression at middle on dorsum, the venter 

 without depression ; first abdominal segment with a median trans- 

 verse linear depression on dorsum and venter, the other segments, ex- 

 cept the apical one, with 2 such depressions which divide the segments 

 into 2 short anterior portions and a longer posterior one ; apical seg- 

 ment different from that of the Alaskan species in having the ventral 

 blood-gills distinct, in the form of an irregular protuberance (PI. 

 XLV, Fig. 6), and the 4 processes round the spiracular disc shorter 

 and of almost uniform length (Fig. 7). 



Described from specimens obtained by me at White Heath, 111., 

 March 12, 19 16, where the larvae were common under leaves and 

 debris that had collected in depressions and holes in tree-stumps sev- 

 eral feet high in a wood along the bank of the Sangamon River. The 

 eggs may have been deposited by late-flying adults after snow covered 

 the ground, when the tree-stumps only were free from it, and this may 

 account for the occurrence of the larvae in this elevated situation. I 

 failed in my attempt to rear the species, and having provisionally 

 placed it in Bibionidae I overlooked it till it was too late to include 

 it in its proper place in this paper. 



Addendum. 2 



The species described below is evidently a limnobiid, 1)ut 1 do not 

 care to venture a suggestion as to its affinities. Though the head bears 

 a resemblance to that of Pediciinae, the apical segment is quite dif- 

 ferent from that of the species of that familv known to me. 



' Genus incertus 



Larva. — Length, 10 mm. ; diameter, i mm. Yellowish testaceous ; 

 head dark brown on the more heavilv chitinized parts, remainder pale 

 brown ; anal respiratory disc dark brown. 



