223 



Larva (PI. XXIX, Fig. 4). — Length, 15-18 mm. Yellowish tes- 

 taceous or slightly olivaceous. 



Head dorsally as in Figure 7, Plate XXXIII, the antennae short 

 and slender (PI. XXXIII, Fig. 2) ; mandibles as in Figure 15, Plate 

 XXXIII, being quite different in form from those of Hexatominae 

 and more resembling those of Limnobia; labium (PI. XXXIII, Fig. 

 3) divided in center, each half with 7 teeth; maxillary palpi with 3 

 joints. Body with rather conspicuous surface hairs which are situated 

 on sHght transverse ridges ; apical segment ( PI. XXX, Fig. i ) with 2 

 short upper and 2 long lower processes which are fringed with very 

 long hairs ; ventral blood-gills 4 in number. 



Pupa (PI. XXIX, Fig. 5). — Length, 10-13 mm. Color as in the 

 larva. 



Thoracic respiratory organs (PI. XXXIII, Fig. 18) slightly long- 

 er than wings, their apices split ; legs ending in a straight transverse 

 line at apex of second abdominal segment ; each dorsal abdominal seg- 

 ment except basal with 5 transverse series of hair-like bristles set on 

 small chitinized elevations which form slight ridges, the posterior pair 

 much more widely separated than the others. Ventral segments with 

 6 such transverse series arranged as on dorsal segments. Apical 

 segment of female composed of 2 pairs of elongate processes which 

 form an acute tip, the lower pair two thirds as long as the upper. 



This species is probably present in every stream and river in the 

 state, as I have found it wherever I have collected in March and 

 April. 



LiMNOPHILA TENUIPES Say 

 LimnopMla tenuipes Say, Jour. Acad. Nat. Sci. Phila.. Vol. 3, p. 21. (1823) 



I have obtained only the pupa of this species. It resembles 

 luteipennis in general shape and in the arrangement of the cephalic and 

 thoracic appendages, but in the armature of the abdomen there is a 

 notable difference. 



Pupa. — Length (exclusive of the respiratory organs), 10—15 mm. 

 Blackish brown. 



Thoracic respiratory organs rather more slender than in luteipen- 

 nis. Abdominal segments, exclusive of the basal dorsal, those covered 

 by the legs, and the apical one, each with 3 transverse pairs of widely 

 separated protuberances, the distance between those of each series less 

 than the distance from either to the lateral margins; distance between 

 the most posteriorly placed pair and posterior margin of segment 

 greater than the distance between the pairs ; posterior margin with 



