58 bulletin: museum of comparative zoology. 



Mecistocephalidae. 

 135. Mecistocephalus nigriceps, sp. nov. 



Type.— M. C. Z. 1,904. Paratypes.— M. C. Z. 1,905, 1,913, 

 1,932, 1,956, 1,961, 1,965, 1,987, 2,012, 2,017, 2,018, 2,135, 2,136, 

 2,138, 2,155-2,158. Fijis: Nadarivatu, Nasoqo, Lakeba Lau, 

 Labasa, Soino Sonio, Lasema, Lomati, Nansori, Wainganitu, Vanua 

 Ava, Vunisia, Suva, Turuca. Solomons: Auki, Florida, Pamua, 

 Fulakora (W. M. Mann). 



This species has a very characteristic color appearance on account 

 of the generally black head, prosternum, prehensors, basal and first 

 dorsal plates, and antennae, and the somewhat brownish appearance 

 of the dorsal plates each of which is typically crossed over the caudal 

 border by a darker band. The head is of the usual long and narrow 

 form, being nearly 1.88 times longer than wide; it is widest anteriorly, 

 narrowing caudad gradually to near the posterior third and then more 

 strongly to the truncate caudal end. The frontal suture, unlike that 

 in M. icnuicuhis, is very clearly evident throughout. Behind the 

 suture and converging gently to the caudal margin are two rows of 

 coarse, deeply impressed puncta which often give the impression of 

 lying in continuous sulci. In front of the suture a pair of coarse 

 puncta and in front of each of these a long seta. Anterior margin 

 of head at middle subangularly emarginate. Lateral pieces of labrum 

 with margins wholly smooth and even; middle piece abruptly nar- 

 rowed at caudal end, but little widening cephalad from there. Man- 

 dibles w^ith nine laminae which are dentate throughout, the teeth 

 smaller toward base; first lamina with only five teeth; external angle 

 simple, not laciniate. Basal plate with a large shallow puncture or pit 

 on each side toward the anterior corner; a few much finer puncta 

 on the more posterior region. Prosternum with very sparse fine 

 puncta; anterior oblique border crossed by two dark chitinous bands 

 projecting anteriorly as slight teeth between which is an emargination. 

 The femuroid is armed at distal end with a long, stout, distally blunt 

 black tooth and the usual smaller one proximad of the obUque suture. 

 The second and third articles with blunt black distally rounded nod- 

 ules or teeth. The tooth at base of claw small, low, broadly sub- 

 conical. Dorsal plates of middle and posterior region strongly bisul- 

 cate and roughened, scabrous or corniculate, the anterior five or six 

 plates smooth excepting for the deep puncta; paired sulci not present 

 on first plate. Ventral plates each with a deep median longitudinal 



