36 ASTACID^. 



tuberculato, margine intemo spinis cluabus, antica majori ; subtus spinis 

 majoribus cluabus anticis, aliisque minoribus internis. Brachio elongate, 

 rostro longiori, extus laavi, intus ante apicem et margine supero tuber- 

 culato, spinis flual)us anteapicalibus oljlique positis ; subtus biseriatim 

 spinoso. Pcdibus tertiis et quartis articulo tertio unguiculato ; pedibus 

 quartis et quintis capitulo basali, quartis elongato-ovali, quintis com- 

 presso, laminato. Pedibus abdominalibus brevibus, rectis, validis, apice 

 vix-bitidis ; parte externa majori, apice barbata, dentil:)us tribus fusco- 

 corneis, subincui'vis ; parte interna dente apicali acuto, obliquo, partem 

 externam fere superanti. 



Fomia II. difFert unguiculis pedum minoribus ; pedibus abdominali- 

 bus basi articulatis, parte externa fere obtusa, dentibus obsoletis ; parte 

 interna dente apicali crassiori, conico. 



Mares formee secundiie variant sa?pe bracliio rostro breviori, inter- 

 duni clielis brevibus, valde angustis, digitis rectis, laevibus ; rostro 

 forma variabili, latiori, marginibus rectis vel subincurvis, acumine 

 angustiori, utrinque magis sinuato. 



Femina differt pedibus anticis chelisque breviorilnis, extus laavioribus; 

 ventre inter pedes quartos antice tuberculo majori, postice bi-vel bisbi- 

 tuberculato ; annulo ovato, fissura longitudinali, labiis alternato-inflatis. 

 Chela interdum basi rubro-maculata. 



Variet. A. 



A great number of specimens from Illinois (LawTi Ridge, Basson 

 Ridge, Evanston, Athens, and Peoria) and from Indiana (Mus. Salem), 

 comprising both forms of the male and the female, which difter as 

 follows: The rostrum has the margins not so arcuated at the base, the 

 margins are more straight ; the epistoma is often more pointed ; the 

 transverse line of the thorax is less sinuated, but usually with a lateral 

 spine. The shape of the first pair of alKlominal legs is different ; seen 

 sidewise the apex more dilated, not hooked behind, the apical teeth 

 are a little larger, and pointed. The female has the ventral segment 

 between the fourth pair of legs not bituberculated, but with a slightly 

 elevated carina ; the ventral segment between the fifth pair of legs is 

 more sharply pointed, its articulation-membrane reaching farther to the 

 tip of the base of the abdominal legs. The hands often have large red 

 basal spots. 



I have seen very full-grown females, the males not so full grown as 

 those from New Orleans. 



Varietas ? B. 



I have seen six adult females from Essex, New Jersey ; New York ; 

 and Beaufort, North Carolina. At first they seem to belong to an- 

 other species. The lamina of the antenna3 is much smaller at the tip ; 

 all liave a lateral thoracic spine ; the rostrum appears narrower in front 



