March, 1921] Macro-Fauna of Mirror Lake 159 



Plathemis lydia Drury, was less common than L. piilchella. 

 Adults were noticed quite often. Only a few nymphs were 

 secured. 



Sympetrum rubicundulum Say. Adults of this, and possibly 

 of other closely similar species, were frequently seen. Reliance 

 was unfortunately put solely on nymphal material. When 

 identification was done only one nymph of this species and of 

 the entire genus was found. 



Pachydiplax longipennis Burmeister. A freshly emerged 

 adult of this species was taken off shore at station 15, on 

 April 22, 1920. This was very early in the season for it is 

 reported for not earlier than May and June in Indiana. (Wil- 

 liamson '99). 



Order Hemiptera. 

 Suborder Heteroptera. 



Aquatic bugs, except surface forms, were restricted almost 

 exclusively to the small pond. The group was an important 

 one in the pond and some forms were abundant in numbers of 

 individuals. The number of species was somewhat less than 

 anticipated but very likely practically all species present at 

 the time of the survey were obtained. Drake found also other 

 species during his collecting (1914-1917). In connection with 

 each family discussion, the additional species he found, are 

 mentioned. 



For classification and nomenclature. Van Duzee's check 

 list ('16) and Catalogue ('17) have been followed, but in the 

 arrangement of the families the more common and generally 

 used one, such as used by Comstock ('16) was followed. 



Family Corixidce. 



Water boatmen were almost exclusively found in the small 

 pond and were commonest late in summer. The largest number 

 of individuals came from the spring, station 13. 



Arctocorixa alternata (Say). In the collected material as 

 far as identified this was the least numerous of three species 

 found ; only a tenth of all Corixids were this. All were taken in 

 station 17. 



Arctocorixa scabra (Abbott AI. S. sp.) Hungerford found 

 this species much commoner in my material, about four times 



