358 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



Hemelytron : Clavus and corium with numerous, intermixed moder- 

 ate and minute punctures, the coarser ones arranged in two rows 

 on each side of claval suture; membranal suture straight, shghtly 

 recurved laterally; membrane slightly surpassing apex of abdomen, 

 length little greater than basal width. 



Propleuron: Punctured; prosternal carinae obsolete. 



Mesopleuron (fig. 86) : Evaporatorium confined to narrow posterior 

 margin, narrowing laterally, evanescent just before reaching lateral 

 margin of segment; remainder polished, distinctly punctured. 



Metapleuron (fig. 86) : Osteolar opening ventrally at base of canal 

 between middle and posterior acetabula; evaporatorium just out- 

 lining canal; remainder polished, with impressed punctures. 



Sternites: Shining, becoming closer and more coarsely punctured 

 laterally; without setigerous tubercles laterad of spiracles. 



Terminalia: Subgenital segment distinctly flared marginally, apex 

 entire; gonostylus as illustrated (fig. 188). 



Female: Very similar to male, measurements averaging larger 

 (see subspecies descriptions below). 



Type data. — Location of type unknown to author. The type 

 locality given by Palisot de Beauvois, "A Agathon, royaume de 

 Benin" in Africa, was apparently in error because StM (1864) ^v^ote, 

 after examining the type specimen, that the specimen was the com- 

 mon American species described by Say as Cydnus ligatus. 



Discussion. — The species is known to occur across the southern 

 provinces of Canada from Newfoundland to Alberta, throughout the 

 United States from Maine to Florida and west to California, and in 

 Mexico to the Isthmus of Tehuantepec. The extensive range brings 

 the insect into many types of territories, so it is not surprising to find 

 that some apparent subspeciation is evident. The material studied 

 could be easily divided into three groups on the basis of color and cer- 

 tain intergrading morphological features. One form is northern, 

 occurring across southern Canada and the northern United States; the 

 second occupies most of the United States and Mexico ; while the third 

 apparently is restricted to a limited area in the central and eastern 

 part of Texas. With a few specimens at the beginning of this study 

 the conclusions reached were decided and clear cut; the three forms 

 appeared sufficiently distinct to warrant being considered full species. 

 But as additional specimens filled in the geographic gaps they also 

 began bridging the morphological gaps so that conclusions concerning 

 the three required revision downward. The subsequent specimens 

 fitted well into the pattern established by the earlier findings but did 

 indicate overlapping of certain structural features that had been 

 considered of specific value. 



