chamberlin: the chilopoda of brazil. 177 



indistinctly, the second to the twentieth plate with three pits, mostly 

 deep and distinct, arranged in the form of a triangle with the median 

 one cephalad, the three more or less clearly connected by more shallow 

 depressions giving sometimes the appearance of a single V- or U- 

 shaped impression. In addition there is a transverse row of three 

 pit-like depressions in front of the caudal margin as in various related 

 species, these pits on some of the more caudal plates lying in a more or 

 less distinct transverse furrow. Last ventral plate long; conspicu- 

 ously narrowed caudad; truncate or slightly inbent at the middle. A 

 distinct longitudinal median sulcus across the entire length. 



Coxopleurae very slightly extended at mesocaudal corners, where 

 they are wholly unarmed. 



First legs with two tarsal spines. Second to nineteenth pairs of 

 legs with a single tarsal spine; twentieth pair with no tarsal spine. 

 Anal legs of moderate length. Prefemur clavately widening from 

 base distad. Wholly smooth. 



Length cir. 78 mm. 



Locality. — State of Matto Grosso: Madeira-Mamore R. R. camp, 

 39, on the Rio Madeira ! (Mann and Baker) . 



One specimen. 



This species lies in the group of forms closely allied with scahri- 

 caudus in which the females are not easily distinguishable. The 

 coloration of the present species is of a characteristic type similar to 

 that of some Scolopendras and also present in 0. caudatus and in 

 several African species of this genus; in these forms the head and 

 first dorsal plate being abruptly and conspicuously different in color 

 from the rest of the dorsum. The species also differs from scabricau- 

 dus in being less strongly scabrous, in having no tarsal spine on the 

 twentieth legs, in having a larger proportion of the third antennal 

 article glabrous, and in having all the teeth excepting the most ectal 

 on each side of the prosternum thoroughly fused together. The type 

 is larger than the maximum measurement recorded for scabricaudus 

 (70 mm.). 



Otostigmus casus, sp. nov. 



Olive-green in color above, brighter along the caudal margins of 

 plates. Head more brown. Antennae brown of greenish caste, 

 the first two articles clearer green. Legs pale brown of dilute greenish 

 tinge. Venter lighter olive, the last ventral plate and the coxo- 

 pleurae more brownish. Prosternum light greenish brown. 



