AQUATIC INSECTS IN KEW YORK STATE 385 



narrowly, and posterior margins in front of scutellum, widely 

 silvery gray; also two narrow longitudinal gray stripes on dor- 

 sum. Or the dorsum might have been described as silvery gray 

 with three very wide velvety black longitudinal stripes, abbre- 

 viated behind. Pleura black, bare; scutellum velvety black; 

 metanotum silvery gray; abdomen velvet-black, the sides of 

 first two or three segments of the ventral surface with a silvery 

 reflection in some lights; legs black, the tips of the fore femora, 

 the basal half of fore and hind tibiae (sometimes the middle one 

 also) the basal two thirds of hind metatarsi, and the extreme 

 base of the second hind tarsal joint, yellow. Fore tibiae with a 

 single spur, middle and hind tibiae with each two ; tarsal claws 

 tridentate. Halteres bright orange-yellow. Wings hyaline, the 

 vein yellow. Length, 3mm. 



In an article by Lugger^, it is stated that inS. tribulatum 

 the male is much smaller than the female, having very large 

 brilliant, red eyes that meet on top of the head; the body is vel- 

 vety black with bright golden yellow and blue spots; the female 

 is gray with black markings. This species is said to be most 

 abundant in Minnesota, where it is called " the black fly." No 

 further description is given; the figures of the male and female 

 agree with the description ofS. vittatum. Some specimens 

 sent by Mr Washburn of the Minnesota Experiment Station, 

 labeled S. tribulatum proved to be S. vittatum. I 

 have specimens of larvae and pupae which belong to S. vitta- 

 tum, which were sent to me by Professor Needham, he having 

 obtained them from Mr J. 0. Bradley of Philadelphia. 



Larva (of S. vittatum). Somewhat mottled gray, the 

 sides of each segment blackish. The larvae and pupae were col- 

 lected by Mr J. 0. Bradley, Philadelphia, 1901. The head is of 

 the usual reddish brown color; the pale yellow antennae long 

 and cylindric, the second joint about one third the length of 

 the first, the third is a pointed process at the tip of the second. 

 The fans have about 40 rays, the cilia being relatively minute. 

 The mandibles are provided with three large apical teeth be- 

 sides the row of secondary ones; the apical pair of bristles is 

 present. The maxillary palpus has a few spines, and a tuft of 

 a few spines on the basal joint. Hypopharynx and labrum ap- 

 parently like those of other species. The labium has an elon- 

 gate middle tooth, those at the end nearly as long, the 



iMinn. Agric. Exp. Sta. Bui. 48, p.207. 



