AQUATIC INSECTS IN THE ADIRONDACKS 565 



prothorax. Another black line incircles the head and prothorax, running 

 through the base of the Y, passing obliquely downward to the gula 

 which is of the same color. The mesothoracic shield is spotted with 

 black and brown. The legs are light brown, the coxa, trochanter, 

 and proximal part of the femur being margined with black. The 

 first and second pairs of legs each have one prominent spur on 

 the tibia. The third pair of legs is more slender and hairy than 

 the others, and the tarsi are terminated by small, feathery brushes 

 instead of hooks. Two rows of respiratory filaments occur on the dorsal, 

 and two on the ventral side. The number of filaments issuing at the same 

 spot on the dorsal side is o, 4, 4, 4, 3, 2, 2, o, o, and on the ventral side 

 o> 35 3> 3j 2, 2, o, o, o, the figures representing the segments in order. 

 These filaments are placed at the anterior margins of the segments. The 

 hooks terminating the body are supported on two-jointed prolegs. 



Pupa. (PI. 13, fig. 3) Length 12 mm. Width 2 mm. Antennae 

 10 mm. Wings 7 mm. Head and thorax white; abdomen pink or 

 green. Two black lines run the length of the body both above and 

 beneath. Respiratory filaments persist on both dorsal and ventral sides. 

 The lateral fringe which forms a loop under the eighth segment is com- 

 posed of soft black hairs. The spurs on the tibiae, which appear as 

 feathery brushes, number 2, 4, 4 on the first, second and third pairs 

 of legs respectively. Hooks pointing backward occur in two rows on the 

 dorsal side of the third, fourth, fifth and sixth segments at the anterior 

 edge of the segments. Two plates with spikes pointing forward are at 

 the posterior edge of the fifth segment. 



Polycentropus lucidus Hag. ? 



Plate 13, figures T-11 



Habitat. Larvae and pupae were found in sandy bottoms with little 

 or no vegetation. Adults were commonly found resting on vegetation 

 in the creek and on the side of the hatchery near the stream. 



Occurrence. Abundant throughout the period of work. 



Case. (PI. 13, fig. 10) Very soft tubular case of fine sand. It is 

 frequently branched and where the insect lies has two distinct layers. 

 The tube is much longer than the larva and is not portable. The 

 position of the larva or pupa is readily recognized. They lie in a part of 

 the case twice the diameter of the rest of the tube. 



Larva. (PI. 13, fig. 7) Length 14 mm. Width 2 mm. Head 

 yellow ; prothorax yellow with black line incircling its rear margin. The 



