AMERICAN HYMENOPTKRA. 25 



SYRPHOCTONUS Foerster. 



Posterior tibia> black, pale at base agilis Cr. 



Posterior tibiae fulvous, black at tip. 



Pleura rufous, scutellum yellow pleiiraliw Cr. 



Pleura and scutellum black robust US u. sp. 



Posterior tibise fulvous, tarsi sometimes dusky. 

 Abdomen entirely black. 



Face with white orbital lines gillettii n. sp. 



Face entirely black iiiellipes Prov. 



Abdomen black, with segments margined with white. • • .lliaculirroiis Cr. 

 Abdomen more or less rufous. 



Thbrax black. . : paciflciis Ci-. 



Thorax red cressoiiii n. sp. 



Syi'phoctonus agilis Cr. {Bnssus), Trans. Anier. Ent. Sac. ii. 111, %. 

 Bas.iiis- fruiitidis Cr., ibid. 9 • 

 MesoUus junctus frov., Faune Ent. Can. ii, 797, 9 . 



9 . — Length 5 mm. Black, with brown antenn?e ; spot on front, spot on man- 

 dibles, tegulse, spot in front, line beneath, triangular spot on sides of mesonotum, 

 tip of scutellum, line between meso- and metapleurse and base of posterior til)i£e, 

 white. Legs, except posterior tibise and tarsi, ferruginous. 



'^.— Diflers in having the entire face, underside of autennge, entire sternum, 

 front of pleurae, post-.scutellum and two spots at base of third segment of abdo- 

 men, yellow. Legs vary from rufous to a light fulvous. 



Abdominal segments in the 9 tend to show more or le.ss signs of rufous, but in 

 the % this characteristic becomes still more marked. 



Thirteen female, three male .specimens ; Illinois, Michigan, South 

 Dakota, New Hampshire, Massachui^etts, New Jersey, Pennsylvania, 

 North Carolina and Ottawa, Canada. 



Syi'pllOCtoiiiiS pleiiralis Cr. (Bassns), Trans. Amer. Ent. Soc. ii. 111. 9 • 

 Bassits syrphicola Ashm., Proc. U. S. Nat. Mus. xij, 439. 



9 . — Length 7 mm. Black, with spot on front, mouth, tegulge, spot in front, 

 broad line on margins of mesonotum, scutellum, post-scutellum, and moi-e or less 

 distinct margins on abdominal segments, yellowish white. Legs, except posterior 

 tibise and tarsi, venter, most of pleura and most of metathorax, honey-yellow. 



% . — Same as 9 > but the face, cheeks, antennne beneath, and the entire ventral 

 and lateral portion of the thorax, except large black spot beneath wings, are yel- 

 lowish white. 



Two female and one male specimens from California and Ohio. 



Syrphoctoiiiis robustiis n. sp. 



% . — Length 7.5 mm. Black, with face, antennje beneath, spot on cheeks, 

 mouth and tegulse, light yellow. Legs honey -yellow, except tips of posterior 

 tibise and tarsi, which are nearly black. The entire body is rather coarsely punc- 

 tured, with metathorax and first three segments of abdomen particularly so. 

 Basal segment of abdomen with an elliptical ridge reaching nearly to the ti]! : 

 segments of abdomen broad, depressed, narrowing at the tip after the third seg- 

 ment ; antenna reddish brown above. Wings hyaline with stigma and veins, 

 except costal at base, brown. 



TRANS. kM. ENT. SOC. XXII. (4) FEBRU.4.RY, 189.0. 



