EUPLECTINI 97 



mesosternum, each fovea having two whorled lumens opening at a common ori- 

 fice; III median and fused; IV and V paired, giving a total nine foveae for the 

 three sternal areas or seven foveae for the mesostemal and metasternal areas. 

 This is a relatively high number and places the species (Table I) in a more 

 primitive group. 



Pararamecia shows certain structural affinities with several genera, for ex- 

 ample Pteroplectiis, Bibloplectus, Ramecia, and Adalmus. It appears to be most 

 related to Pteroplectus of Chile, but the latter genus has the prosternum entirely 

 carinated medianly and longitudinally, and the females have seven sternites. 

 Ramecia in North America, Panaramecia of the Canal Zone, and Biblomimus 

 of the Lesser Antilles have many things in common, and structurally there is 

 an interesting gradation in the prosternal carina, which is entire in the latter, 

 microscopically discoverable as a minute fold between the prosternal foveae in 

 Panaramecia, and absent in Ramecia. Panaramecia and Ramecia are related 

 through the development of the secondary tarsal claws, but Ramecia and 

 Biblomimus have seven sternites. Such comments are given to reemphasize the 

 lack of a complete tabulation of comparative structural details. Until more is 

 known the phylogenetic relationships will be poorly understood. 



PTEROPLECTUS (Raffray, 1898) 

 grandicornis (Schaufuss). 1879. Chile. (Euplectus). Genotype. 



THESIASTES (Casey, 1893) 



Casey had the following to say regarding his genus (pp. 457-8) : 



"In general organization the species of this genus resemble Euplectus, 

 but have the body much more minute, the head smaller and especially shorter, 

 the frontal truncature narrower, the eyes relatively larger and more prominent, 

 the tempera shorter and the abdomen completely devoid of dorsal carinae, 

 although deeply impressed at the base of the first two or three segments. In 

 spite of these differences I should have probably regarded them as one of the 

 subgeneric groups of Euplectus, had it not been for the fact that the male 

 sexual modifications at the apex of the venter were found to be of a com- 

 pletely different type. The large, rhomboidal, tumid and carinate seventh 

 ventral in the male Euplectus is here replaced by the oval, flat, laterally en- 

 closed pygidium so characteristic of Ramecia, Actium, and other more or less 

 widely separated genera; this indicates a real divergence from Euplectus far 

 more pronounced than might be inferred from the general organization. The 

 male sexual organs must indeed be remarkably different in structure." 



I am in entire agreement with Casey that Euplectus may not logically con- 

 tain males with the seventh sternite in two valves, and with a single valve. 

 Thesiastes has many structural features shared by Euplectus, but is not to be 

 included in the latter genus. Thesiastes now holds some fourteen species, dis- 

 tributed over the world, including South America, Antilles, North America, 

 and Asia, and the East Indies. The species have a general resemblance to 

 Ramecia in habitus and pubescence, are similar to Euplectus in many ways, 

 and there is an odd resemblance to Thesium in outline. The tarsi have a large 



