376 



— Head with long, sharp, forward-directed thorns; abdomen with 



long and short straight thorns alternating 2 



2. Thoracic spiracle slightly elevated, rugose, without well-defined 



reniform area (PromacJius) 3 



— Thoracic spiracle with distinctly elevated, well-defined, reniform 



area 5 



3. Lateral cephalic process consisting of 3 thorns, the upper one bifid 



or sometimes duplicated so that the process appears quadri- 

 spinose; the last 5-6 thorns on lateral extremities of transverse 

 armature of abdominal segments 2-7 very slender, their bases 

 swollen but not fused ; eighth ventral abdominal segment of male 

 with 4 thorns Promaclius fitchii (p. 383) . 



— Lateral cephalic process consisting of 3 simple thorns 4 



4. Large species, averaging over 25 mm. in length ; last 4-5 thorns on 



lateral extremities of transverse armature of dorsal abdominal 

 segments 2-7 stout, flattened and rather wedge-shaped, their 

 bases fused; intermediate short thorns present between the long 

 ones on tranverse series of seventh dorsal abdominal segment. . . . 

 Promaclius vertehratus. 



— Smaller species, about 20 mm. in length ; last 4-6 thorns on lateral 



extremities of transverse armature of dorsal abdominal segments 

 2-7 slender but not fused ; intermediate short thorns absent from 



transverse armature of seventh abdominal segment 



.....' Promachus sp. 



5. Apices of fore tarsi extending very distinctly caudad of apices of 



wings (Deromyia) 6 



— Apices of fore tarsi not extending to apices of wnngs 7 



6. Ventral abdominal segments 3-7 each with an uninterrupted trans- 



verse median series of closely placed hrisiles .Deromyia ivintJiemi. 



— Ventral abdominal segments 3-7 each with 3 short transverse series 



of rather stout spines — one on each side and one in middle (i. e., 

 the series twice interrupted) Deromyia discolor (p. 384). 



7. Lateral cephalic process with 5 distinct thorns 



Ceraturgus cruciaius (p. 379) . 



— Lateral cephalic process with 4 distinct thorns 



Dasyllis sp. ? (p. 382). 



— Lateral cephalic process with 3 distinct thorns 8 



8. A pair of strong bristles at middle of seventh ventral abdominal 



segment situated slightly caudad of the transverse series (some- 

 times also distinguishable on sixth) {Erax) 9 



— Armature of seventh ventral abdominal segment consisting either 



of a complete transverse simple series of bristles or of a centrally 

 interrupted series, caudad of which there is no armature on the 

 segment 10 



9. The pair of thorns at base of middle leg very short and stout ; post- 



spiraeular area of first abdominal segment with 7-9 spines; up- 



