1.5 

 1.5 

 1.1 

 2.5 



308 PROCEEDINGS OF THE ACADEMY OF [March, 



Measurements. 



(^ ? 



Total length, 7.5 mm. l?-0 "^f^" 



Length of pronotmn, ^'^ ]] 



Width of pronotmii, ^'^ u 



Length of anal segment, 4 "^ 



Length of forceps, 1-5 



An additional immature specimen from the type locahty was also 

 examined. 



Genus ANCISTROGASTER Stal. 

 1855. Ancistrogaster Stal, Ofv. Kongl.-Yet. Akad. Forh., XII, p. 349. 

 Type: A. luctuosus Stal. 

 Ancistrogaster tolteca (Scudder). 



1876. Forficula tolteca Scudder, Proc. Boston Soc. Nat. Hist., XVIII, p. 261 

 [Mexico.] 

 Three males; Orizaba, Vera Cruz, Mexico. January 9-16, 1892. 

 (H. Osborn.) [U. S. N. M.] 



Previous records: Orizaba and Atoyac, Mexico, and Coban, Guate- 

 mala. 

 Ancistrogaster gulosa Scudder. 



1876. Ancistrogaster gulosa Scudder, Proc. Boston Soc. Nat. Hist., XVIII, 

 p. 259. [Puebla, Mexico.] 

 Fifteen specimens; eight males, seven females; Orizaba, Vera Cruz, 

 Mexico. January 9-16, 1892. (H. Osborn.) [U. S. N. M.] 



Genus OPISTHOCOSMIA Dohru. 

 1865. Opisthocosmia Dohrn, Entom. Zeituug, Stettin, XXVI, p. 76. 



Type: By selection, 0. eenturio Dohrn. 

 Opisthocosmia (Sarcinatrix) anomalia n. subg. et sp. 



Types: d^ and 9 ; Turrialba and San Carlos, Costa Rica. (Schild 

 and Burgdorf.) [U. S. N. M.] 



This form appears to differ from all the other members of the genus 

 Opisthocosmia, in the forceps of the male being parallel throughout 

 their entire length. This, as well as the peculiar structure of the 

 subgenital plate, has caused me to create a new subgenus for the 

 reception of the species. 



(^ Size medium ; form rather slender and graceful ; surface polished 

 and furnished with long hairs. Head rather broader than the prono- 

 tum; interorbital region tumid and bearing two median longitudinal 

 impressions; eyes prominent, ovate in outline; antenna? with the basal 

 joint elongate, robust, of greatest thickness in the.distal portion, second 



