CHAMBERLIN: HENICOPIDAE OF AMERICA NORTH OF MEXICO. 17 



longitudinal median sulcus and, on each side of this, two or three sulci 

 a little diverging cephalad. Form of ninth and eleventh plates varying 

 with age and stage of chitinization; in larger, fully chitinized indi- 

 viduals the caudal margin is straight with the corners not excised, or 

 occasionally shortly so on one side; in small individuals, on the con- 

 trary, the corners are usually more obliquely and more clearly excised, 

 much as infulmcornis; while intermediate specimens have the eleventh 

 straight like the thirteenth, the ninth still retaining the obliquely 

 truncate or excised corners. (Plate 2, fig. 4). 



Ventral plates roughened with rather fine transverse furrows or 

 sulci of which one or two toward the caudal margin are deeper. On 

 most plates a fine longitudinal furrow parallel with each lateral margin. 

 Usually last three or four plates marked on each side with several dis- 

 tinct furrows running obliquely from the edge mesocephalad; last 

 segment finely roughened but lacking the transverse sulci except 

 commonly the deeper caudal one. 



Anal legs longer than in the other species, the length of body being 

 only about 2.35 times greater; longer than penult legs in ratio 53:33, 

 or about 1.6 times longer. Tibia 5.3 times as long as thick; first 

 tarsal joint eight times as long as thick; and the second tarsal joint 83 

 times longer than thick. Greatest thickness of femur to greatest 

 thickness of tibia as 1.5: 1. Thickness of tibia to that of first tarsal 

 as 1.74: 1. Lengths of third, fourth, fifth, sixth, and seventh articles 

 to each other as 37:40:46:40:30. 



Coxal pores small and circular; 2, 2, 2, 2 to 3, 3, 3, 3, but most often 

 2, 3, 3, 2, 



Claw of gonopods in fully grown females nearly straight, less curved 

 than in the other species; flattened or excavated on mesal side; more 

 curved in younger specimens. Basal spines 2+2; conical; the outer 

 on each side robust, the inner being relatively smaller than in the 

 other species and usually more acute than the outer. 



Length 7-9 mm. in types; will probably be found to range consid- 

 erably above this. 



Praemnturus. Living specimens secured at Las Vegas, Nev., were 

 light brown with a marked violet tinge, the latter fading in alcohol. 

 Head a little darker and weakly reddish. Antennae (alcoholic speci- 

 mens) yellowish brown; more greyish, less pigmented, proximally. 

 Legs pale. A specimen from Claremont, Cal., has dorsum light brown, 

 with the first and last plates darker, especially along the caudal bor- 

 ders; head dark caudad of frontal suture and blackish on sides about 

 ocelli which have a decidedly bluish cast, and the frontal region orange 



