NO. U.S7. NORTH AMERICAN DIGGER WASPS— FERNALD. 357 



Isodontia tibialis Patton, Proc. Bos. Soc. Nat. Hist., XX, 1880, p. 381. 



SpJic.c {Isodontia) tibialis Koiil, Ann. natur. Hofnius?. Wien, V, 1890, pp. 122 



and 379. 

 Isodontia tibialis Ashmead, Psyche, VII, 1894, p. 64. 

 Sphex tibialis Packard, Journ. N. Y. Ent. Soc, IV, 1896, p. 158. 

 Isodontia tibialis B.. Fernald, Can. Ent., XXXV, 1903, p. 269. 



Body quite large, black; outer segments of the legs ferruginous 

 3^ellow; wings fuliginous with a violet reflection; pubescence golden 

 to j^ellow. 



Female. — Head black, rather quadrangular from above, the cheeks 

 being quite full; ch'peus arched laterall}", quite long, its anterior 

 corners rounded, the anterior margin slightly excavated from each 

 corner to near the middle, where there is a projecting tooth with a deep 

 notch in the middle separating the two teeth; this margin of the 

 clypeus is bare and somewhat ferruginous in some cases, the rest of 

 the plate being l)lack, 3^ellow pubescent, and covered quite closely 

 with long, brown hairs; frons yellowish pubescent to the in.se rtions 

 of the antenna?, higher at its sides, bearing long, brown hairs; frontal 

 suture evident; lateral ocelli but a short distance behind the median 

 one, the three lying in a curve rather than marking the corners of a 

 triangle; vertex sparsely punctured, liearing long hairs; cheeks broad, 

 half the width of the eye, narrowing sharply below; with a trace of 

 yellow pubescence just behind the middle of the eye; with long hairs, 

 longer, coarser, and more abundant below; inner margins of the eyes 

 slightly convergent toward the clypeus; antenniB black, the outer por- 

 tion rather brownish or grayish sericeous; scape with numerous short, 

 brown hairs and sometimes slightly sericeous; first segment of the 

 filament the longest; mandibles short, with three teeth of about etjual 

 length; the teeth black and the base blackish; the rest of the mandible 

 ferruginous to dull yellow; with faint punctures and scattered hairs. 



Thorax. — Neck short, broad; collar lising obliquely backward from 

 the neck to a quite sharp dorsal edge which is evenly rounded later- 

 ally and is strongly yellowish sericeous, almost pubescent; posterior 

 face vertical, not closely appressed against the mesonotum; protho- 

 racic lobe slightly yellowish pubescent behind; the entire collar 

 sparselj^ covered with dark brown hairs; mesonotum bent stronglj^ 

 downward in front and at the sides in front of the tegulw; its surface 

 finely, sparsely punctured and l)earing short, brown hairs; with an 

 anterior, median, impressed line and parapsidal lines perceptible; 

 scutellum rather })road from front to rear, flattened above; its sides 

 quite strongly depressed; with punctures and hairs like those of the 

 mesonotum; postscutellum narrow, evenly rounded, with scattered, 

 fine punctures and hairs; dorsum of the median segment rather 

 coarsely, very closely punctured; with a broad, slight median depres- 

 sion posteriorly, and with many brown hairs; angle between the dor- 

 sum and the posterior end slight, located just above the fovea which is 



