1864.] 



133 



Female. — Black, subopaque ; face, cheeks and the thorax have a 

 more or less distinct silvery-sericeous appearance in certain lights; man- 

 dibles, except base and apex, yellowish-ferruginous ; antenna? blackish- 

 piceous above and rufo-piceous beneath, sometimes the basal joint be- 

 neath is rufous, and the joints towards the tip are also sometimes ru- 

 fous ; neck long ; thorax roughly and confluently punctured, somewhat 

 transversely rugose above ; tegulae and tubercles mostly pale rufous, 

 sometimes piceous ; wings hyaline and beautifully iridescent ; the two 

 anterior pairs of legs are pale rufous, base and tips of their tibiae, and 

 the base of their tarsi whitish, their femora sometimes obfuscated ; the 

 anterior and intermediate coxae are piceous, the anterior pair sometimes 

 rufous, posterior pair always black and rugose; posterior legs black, 

 their trochanters rufous, their tibiae and tarsi near the base white, the 

 latter sometimes reduced to a dot or subobsolete ; abdomen long and 

 slender, tip of the second and third segments on each side broadly 

 rufous, sometimes the tip of the fourth segment is obscurely so ; in two 

 specimens the rufous coloring is indistinct on the second and third seg- 

 ments ; ovipositor about as long as the body, fulvous, valves black, tip- 

 ped with white. 



Hah. — Massachusetts. Mr. James Ridings. 



5. F. incertus, n. sp. 



Black : second, third and fourth segments of tbe abdomen each with a fer- 

 ruginous spot on each side at base: ovipositor very short. 



Femah'. — Black ; antennae slightly tinged with piceous beneath to- 

 wards the tip. Thorax dull black, without distinct punctures, minutely 

 shagreeued ; metathorax roughly punctured. Wings obscure hyaline, 

 nervures and stigma black. Legs black, the two anterior pairs with 

 the base of their tibiae reddish. Abdomen black, apex much broader 

 than usual ; sides of the second, third and fourth segments at tip, fer- 

 ruginous; ovipositor very short, about one line in length, ferruginous, 

 valves black. Length 4^ lines; expanse of wings 5 lines. 



Afa/e. — Resembles the female, but the abdomen is more slender, all 

 the tarsi, the two anterior pairs of femora and the posterior femora at 

 base, more or less pale ferruginous. 



Hub. — Rocky ?.Iountains, Colorado Territory. 



This appears to agree very well with the description of F. assecfdtor 

 Linn., of Europe, with the exception of the coloring of the legs. 



