. TEIDACTTLUS. 207 



incompletely described by Haldeman, the size being the same and the other North- 

 American species all smaller. It differs from T. fissipes in the form of the anterior 

 tibiae of the male, these not being more or less notched on their apical margin. 



This is the largest American species of the genus. It is particularly distinct by its 

 size. T. mixtus closely resembles T. brunneri, Sss., and T. thoracicus, Guer., in general 

 facies, but differs from both of these Indian species by the form of the anal pieces. 



5. Tridactylus (Heteropus) histrionicus, sp. n. (Tab. XL %g. 1-5.) 



Minimus, nigro- (vel fusco-) et sulfureo-multipietus. Antennae nigra vel flavo-annulatae. Caput fuscum, 

 frequentius flavo-punctatum, palpis flavis. Pronotum flavum, fusco-multipictum, vel nigrum, marginibus 

 flavis, disco flavo-punctato, retro flavo-marmorato. Elytra fusca, flavo-bifasciata. Alae abdomen supe- 

 rantes, fusco-nebulosae, margine dorsali anguste fusco. Pedes antici flavi, anterius brunnei, maculis et 

 genubus flavis. Pedes intermedii nigri, femoribus flavo-fasciatis, tibiis flavo-tripunctatis. Pemora 

 postica nigra, flavo-multipicta, vel flava, nigro lacerato-bifasciata. Tibiae posticae flavae, apice brun- 

 nescentes, subtus brunneae, lamellis natatoriis destitutae marginibusque integris, supra apice bicarinatae 

 (carinis spinas appressas imitantibus). Calcaria supera subrecta, apice baud uncinata. Metatarsus nullus 

 (tuberculiformis). Abdomen nigrum, subtus flavum, supra segmentis flavo-limbatis, ano nigro ; cercis et 

 appendicibus analibus nigris. Cercorum articulus secundus brevis. Tibiae anticae marium (fig. 4) illis 

 feminarum similes. — Long. 4 millim. 



Yar. a. Alae abbreviatae vel rudimentales, inconspicuae. — h. Alae caudatae, sordide hyalinse. 



Variat in pictura multifarie, plus minus flavo-, vel fusco-ornatus, nonnunquam pronoto toto nigro, angulis 

 posticis flavis ; vel ipse totus niger, punctis rarioribus flavis conspersus ; interdum abdomine subtus fusco, 

 segmentis omnibus flavo-limbatis. 



§. Yentris segmentum penultimum (fig. l,i) triangulare, angulatum. Ultimum segmentum (yi) subqua- 

 dratum, angulis rotundatis, per sulcum divisum (nonnuuquam subbilotatum). 



d . Penultimum segmentum ventrale (fig. 2, s) transversum ; ultimum {%) subquadratum, integrum. 



Figures. — Pig. 1, extremity of the abdomen from beneath, 5 •■ -Fig. 2, ditto, $ ; — 8, penultimate ventral 

 segment; — 9, si, terminal segment or infragenital plate; — c, cerci; — a, anal appendages. — Pig. 3, extremity 

 of the abdomen $ , from above ; — 9 i, terminal segment ; — c, cerci ; — a, anal appendages ; — vs, supra-anal 

 plate. — Pig. 4, anterior tibia and tarsus (outside). — Pig. 5, intermediate tibia and tarsus. 



Hal. Noeth Ameeica, Texas, Dallas (Boll). — Mexico, Atoyac in Vera Cruz, Frontera 

 and Teapa in Tabasco (H. H. Smith). 



This little species forms in the genus a particular type on account of the hind tibite 

 being without teeth, but presenting above at the tip, on each side, a carinule, which 

 has the appearance of a styliform appendage, not separated from the tibise. The two 

 superior spurs also are of exceptional form — somewhat elongate, slender, cylindric, not 

 hooked at the tip, terminated by stiff setae only. The inferior spurs are scarcely toothed 

 at the tip. 



[6. Tridactylus (Heteropus) histrio, sp. n. 



Minutus, niger vel fuscus, multifarie flavo-pictus ; T. histrionico simiUimus. Tibiae posticae marginibus integris, 

 nee serratae nee lamellis instructae, sed apice spinis 1 : 2 mobiles gerantes ; calcaribus superis gracilibus, 

 uncinatis, inferis longissimis, J- tibiae aequantibus. Metatarsus posticus abortivus, non perspicuus. 

 Abdomen superne fuscum, segmentis flavo-marginatis, subtus frequenter flavis ; cercis fuscis, articulo 

 apicali flavido ; appendicibus analibus brunneis.— - Long. corp. 5 millim. 



