202 



Taxonomic notes . In the first paragraph of his 



description for Ischyrus chiasticus Boyle (1954:43-46) 



stated: 



This form appears to be a possible subspecies 

 of Ischyrus quadripunctatus (Olivier) , yet both in 

 color pattern and in geographical range, so far as 

 is known, it constitutes a distinct population. 

 It is known from the mountains of southern Arizona 

 and from the Mexican State of Sinaloa (one 

 specimen) ; thus it apparently ranges from southern 

 Arizona into Mexico along the Sierra Madre 

 Occidental for an unknown distance. Its closest 

 relative, I. quadripunctatus graphicus Lacordaire, 

 is found from extreme southern Texas south into 

 Mexico (presumably along the Sierra Madre 

 Oriental) and on into Central America. If 

 intergrading populations of these two forms are 

 eventually found, they will almost certainly occur 

 in southern Mexico where the two Cordilleras 

 become confluent. The prairies and deserts of 

 northern Mexico, western Texas, and southern New 

 Mexico support few trees upon which grow the 

 fungous food of these beetles. 



Little information can be added to this, although 

 specimens from further south into Mexico (state of Morelos) 

 have been studied, with little or no notable variation in 

 color pattern from the Arizona specimens. 



No specimens were studied with intermediate color 

 pattern. The ranges of these forms still appear to be 

 distinct and isolated. Distinguishing morphological 

 characters are apparently lacking, including the genitalia. 

 Boyle (1956:135-136) mentioned a slight difference in the 

 male median lobe between I. chiasticus and I. q. 

 quadripunctatus, but stated "...the two must be placed side 

 by side to see such differences, and even then positive 

 identification would be hazardous." 



