118 SUB-GENUS CEPHUS. 



known from it by the pronotum being entirely black, 

 by the vertex being without any yellow marks, the 

 marks on the abdomen being very much smaller, and 

 the fourth segment is entirely black, while the second 

 cubital cellule is shorter compared to the third. The 

 d is readily separated from that of linearis by the 

 femora and coxae being entirely black. 



Sub-genus CEPHUS. 



Antennce eighteen to twenty -three- jointed, apex clavate or 

 sub-clavate. The basal two joints of maxillary 

 palpus subequal. Sixth scarcely double the length 

 of fourth. Eyes reaching to near the base of the 

 mandibles. 



1 (2) Hind tibiae with only one spine. Antennae longish, third joint 



almost shorter than fourth. Posterior legs fuscous. Ovi- 

 positor short. Abdominal segments two to six, bordered with 

 yellow. Antennas usually 23-jointed. Arundinis. 



2 (1) Hind tibiae with two spines. 



3 (4) Abdomen entirely black, antennae 18 20-jointed, clavate. 



First recurrent nervure interstitial. Phthisicus. 



4 (3) Abdomen marked or banded with yellow. 



5 (6) A longish spot on each side of the abdominal segments, the 



whole forming an almost continuous band. Tdbidus. 



6 (5) Abdomen with two or more yellow belts. 



7 (8) Apex of abdomen black, a yellow band only on the fourth and 



sixth segments. Head sub-cubical, vertex emarginated. 

 Length 7 8 lines. Niger. 



8 (7) Apex of abdomen yellow. Head transverse, vertex scarcely 



emarginated. Length 2 4 lines. 



9 (10) Abdomen with two yellow complete bands, antennae brownish at 



apex. Breast and vertex pilose. Hind tibiae and tarsi tes- 

 taceous. Pusillus. 

 10 (9) Abdomen with more than two complete bands, posterior tibiae 

 and tarsi fuscous. Antennae black. Pygmseus. 



Males. 



1 (2) Breast, coxae and femora more or less yellow. Pygmseus. 



2(1) Breast black. 



3 (4) Abdomen entirely black. Phthisicus var. 



4 (3) Abdomen banded with yellow. 



5 (6) With three complete bands (the fourth, fifth and sixth seg- 



ments), antennae 18 20-jointed. Phthisicus. 



6 (9) With only two complete yellow bands. 



