160 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



Diagnosis: A genus of the Arinolinae with several very distinctive 

 features, most outstanding of which is the shape of the anterior 

 gonopods. These gonopods are in general similar to those of Arinolus 

 except that the coxites are more approximate mesially and are sep- 

 arated by an elongate ligulate process formed by two appressed 

 flattened folds of membranous intersegmental sclerotized tissue. The 

 anterior face of the coxites is superficially divided by distinct lateral 

 grooves as in Arinolus. The posterior gonopods are rather heavy and 

 short, the telopodite distally modified into a thin membranous calyx, 

 which is subtended by a long slender acuminate solenomerite. Body 

 form slender and parallel except for the enlarged sixth and seventh seg- 

 ments. Collum less narrowed at sides than normal for the family, the 

 anterior margin concave and with a slight marginal ridge, the caudal 

 margin convex and with a few subterminal striae. Metazonites dis- 

 tinctly punctate. Claws of first two pairs of legs of males enlarged, 

 those of following legs somewhat reduced in size. Coxal lobes of third 

 leg pair prolonged and extending back over those of fourth, which are 

 erect and subtriangular processes. 



Discussion: This genus was originally compared only with Messi- 

 cobolus and Eurelus, neither of which are very closely related to it, 

 while the obvious affinity with Arinolus was overlooked. 



As presently treated, this genus is known only from two species 

 collected at the southern end of the Mexican Plateau, from which 

 region, however, a number of additional forms are to be expected. 

 Tarascolus is discussed at greater length in connection with Scobinomus , 

 the genus that follows below. 



Tarascolus bolivari Chamberlin 



Tarascolus bolivari Chamberlin, 1943a, p. 26, figs. 46-50 (male holotype in the 

 Chamberlin collection, from Zitacuaro, 1,900 m., Michoacdn, Mexico, collected 

 on July 13, 1941, by C. Bohvar). 



In Chamberlin's paper, figure 46 is stated to represent the right 

 posterior gonopod of Messicobolus totonacus. However, this figure 

 bears little resemblance to figure 45, which is also said to be of the 

 posterior gonopod of the same species, and since the figure is almost 

 identical with the corresponding gonopod of the closely related 

 Scobinomus serratus (see fig. 12, c), it seems reasonable to assume thai 

 some mixup in numbering occurred and that figure 46 actually repre- 

 sents the posterior gonopod of T. bolivari, which is not otherwise il- 

 lustrated although stated in the text description to be shown. 



Tarascolus clarus Chamberlin 



Tarascolus clarus Chamberlin, 1943a, p. 26, fig. 51 (male holotype in the Chamber- 

 lin collection, from Santa Rosa, Distrito Federal, Mexico, collected on June 

 28, 1942, by M. Cardenas). 



