326 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



other Syrphus (sensu strict); the hypopygium of the male is much 

 smaller than in Syrphus, entirely concealed under the fifth segment ; 

 the front remarkably convex in both sexes. These characters fully jus- 

 tify the formation of a separate genus, which I will call Catabomba, in allu- 

 sion to the mode of flight of the species (from xarafiofxpiw, I am hum- 

 ming round). 



2. Syrphus intrudens n. sp. — Male. — Eyes pubescent ; face brown- 

 ish-yellow, with a broad black stripe in the middle, abbreviated 

 before the antennae, and narrower than the yellow portion of the 

 face on each side of it; the black is prolonged along the oral bor- 

 der to the black cheeks, which have a slight greenish reflection ; 

 antennae black, third joint sometimes slightly reddish at the base ; 

 front and vertex black, with a greenish reflection and black pile; 

 occiput beset with a fringe of fulvous pile. Thorax dark metallic- green, 

 clothed with fulvous pile, especially conspicuous on the pleurae ; scutel- 

 lum with a shade of dull yellowish under the strong greenish-metallic 

 luster ; its pile is black ; a few fulvous hairs on the sides only. Abdomen 

 black, very little shining; on the second segment two oblong yellow 

 spots, not reaching the lateral margin ; on the third and fourth seg- 

 ments, a pair of deeply lunate spots, club-shaped at both ends, touching 

 the anterior margin on one side, broadly contiguous to the lateral mar- 

 gin on the other ; the deep excision on them has a triangular shape ; 

 fourth and fifth segments with a narrow yellow posterior margin. Hal- 

 teres with a lemon-yellow knob ; legs reddish ; anterior femora black on 

 their proximal half; hind femora black, except the tip ; hind tibiae with 

 a brown ring in the middle ; the other tibiae also slightly marked with 

 brown; tarsi brownish above. Wings distinctly tinged with brownish; 

 stigma brownish. Length about 10 mm . 



Hob. — In the woods of the Coast Range, in the spring; Lagunitas 

 Creek, April 15-20; also received from Mr. H. Edwards three males. 



Very like Syrphus amalopis O. S. from the White Mountains, X. EL, 

 but the pile on the occiput is bright fulvous, not pale yellowish-white ; 

 there is more fulvous pile on the thorax ; the abdominal spots are a lit- 

 tle larger, their inner club-shaped end more clumsy, the emargination 

 deeper ; the legs are less dark-colored ; the facial tubercle less promi- 

 nent. Nevertheless, the resemblance is very striking. S. amalopis seems 

 to be a very variable species ; in the females which I have seen, the 

 lunate abdominal spots were dissolved in two, thus forming transverse 

 rows of four spots on segments 3 and 4; the cross-bands sometimes 

 touch the lateral margins, sometimes not. The same variations may 

 occur in S. intrudens. 



3. Syrphus lapponious Zetterstedt, Dipt. Scand, ii, 701, 3. — 

 In my above-quoted essay on Syrphus (p. 149), I have referred to 

 this species a number of specimens from the Northern Atlantic States 

 and the British Possessions, which agree in all respects with Mr. Zetter- 

 stedt's description, and some of which, sent by me to Dr. Loew, were 



