58 Psyche [April 



and bearing on the inner side a row of little spines, quite erect all the way, the ter- 

 minal one not large; the other femora and tibiae quite shining; hal teres yellow to 

 dark yellow, the knob not with a darker spot, the stem dark at base. Wings 

 almost hyaline, without spots, the veins yellow at base as far as the middle of the 

 basal cells and the first vein farther, the costa however only pale halfway to the 

 humeral. Abdomen greenish, short, with whitish hairs on the sides and below, 

 fourth sternite divided, behind it a pair of blackish protruding flaps. 



Length, 3.9 mm.; of wing, 4.2. 



Female. Face generally not bright below, yet distinctly green in the concave 

 upper portion; front coxse with the black spines quite small; dorsum of thorax 

 more opaque, hardly shining. 



Length, 4.8 mm.; of wing, 5.5. 



Thirty-two specimens: Battle Creek, Mich.; McHenry, 111. 

 Lawrence, Kans. ; Brookings and Pierre, S. D.; Austin, Tex.; 

 Moscow and Craig's Mt. in Idaho; Palo Alto and Pacific Grove, 

 Cal.; Longmire's Springs and Coulee City, Wash. The last and 

 the material from Texas and Illinois are from Professor Melander, 

 Dates: Austin, Texas, Oct. 29 and Dec. 25; Palo Alto, Apr. 12; 

 Pacific Grove, May 6; Brookings, S. D., Apr. 25; Longmire's, Aug. 

 2; Coulee City, June 25 and July 13. The species evidently has 

 a long season as well as a wide distribution. The dated speci- 

 mens from Brookings have some personal interest, as I collected 

 them in the spring of 1890, just after I had decided, under the 

 advice of Professor A. J. Cook, to take up the Diptera as a 

 specialty. 



Hydrophorus breviseta Thomson (figs. 10, 11). 



Male. Occiput green, with a bluish pruinosity, postvertical bristles only two; 

 orbitals extending about two thirds of the way down behind the eye, beard yellow, 

 numerous stiff spines below the neck; front opaque brownish; face green above, 

 below with some brown pollen; the eyes reach as far down as the lower edge of the 

 face, and the cheek is in the form of a very narrow vertical plate; palpi dark brown 

 with hairs of the same color; antennae small and very short. Dorsum of thorax 

 rather brown, not shining, with a row of small lighter spots on each side, where 

 they intervene between the dorsocentrals; four large scutellars; pleurse rather 

 green in the middle, whitish pruinose below; propleura with conspicuous yellowish 

 hairs and one black bristle; mesosternum with thin, pale hairs; halteres rather 

 deep yellow. Front coxae with scattered pale hairs and at tip a few small black 

 spines; front femur thick at base, on its lower side at extreme base about five little 

 black spines with some whitish hairs, then about the middle a row begins of very 

 long bristles which decrease rapidly; front tibia with a swelling on the inner side, 

 largest just beyond the middle, followed by a deep excavation, beyond which to 



