14 Psyche [February 



tandon, the fore femora are more slender and have no trace of 

 the siibapical notch commonly present in that species, and the pro- 

 notum is more distinctly carinate on the posterior part of the 

 anterior lobe. The hind legs of protensa are longer than in either 

 of the other species, reaching to the tip of the air-tube, the femora 

 reaching to the apices of the hemielytra, whereas in americana 

 the legs reacli only to about the middle of the air-tube and the 

 hind femora only to the penultimate segment of the abdomen; the 

 hind legs of kirJcaldyi slightly surpass the middle of the tube. 



R. americana is easily the most abundant species of the genus 

 in Michigan and in Minnesota ; R. hir'k.aldyi is much less generally 

 distributed, but is sometimes locally common, especially in waters 

 containing a relatively high content of calcium salts in solution; 

 and R. protensa is the least common of the three species. 



Palmacorixa huenoi Abbott. This is a common Corixid in the 

 Atlantic states, but has not hitherto been reported west of Ithaca, 

 N. Y. During August, 1920, I took two specunens at Ann Arbor, 

 Michigan, from among waterweeds in the Huron River. 



Palmacorixa gillettei Abbott. During June and September, 

 1919, I found this Corixid abundant in the Galien Eiver a few 

 miles north of Three Oaks, Michigan. The species was previously 

 reported only from Colorado. 



Corixa verficalis (Yieher). The range of this species extends 

 from the Atlantic coast west at least to Missouri. I found it 

 abundant in the Galien River in June, in company with P. gillettei, 

 but it was not taken here in September. In Mr. Bueno's collec- 

 tion there are two specimens from Creve Coeur Lake, Missouri, 

 labelled Arctocorisa calva (Say) by Professor Abbott. 



In his description of Palmacorixa gillettei Professor Abbott 

 says,^ "Superficially it resembles calva .Say." I believe that the 

 calva to which Professor Abbott compares his new species is cer- 

 tainly Corixa verticalis — especially since I have seen the specimens 

 referred to above — since this species does have a superficial resem- 

 blance to P. gillettei, whereas the true calva is a very different 

 insect. 



Corixa macroceps (Kirkaldy). This species was described from 



»Ent. News, xxiii, p. 339, 1912. 



