60 BIOLOGICAL SURVEY OP 



PoLYTLAx Enderlein 



P. spiNULOSA (Burmeister). Occurs on rats, etc. 



Haemodipsus Enderlein 



H. VENTRicosus (Deiinv). Occurs on the rabbits. 



CoRixiDAE. The Water-boatman 

 Arctocorisa Wallengren 



A. DECOROTELLA Huiigf. S. W. Hai'bor, July 14-18. 

 A. coNOCEPHALA Huugf. S. W. Hai'bor, July 15. 

 A. VULGARIS Hungf. Salisbury Cove, Aug. 10. 

 A. SERiATA Abbt. Salisbury Cove, Aug. 11. 

 A. NiTiDA var. MINOR Abbt. Salisbury Cove, July 18-Aug. 10. 

 A. MAEROPALA Huugf. S. W. Harbor, June 18. 

 A. iNTERRUPTA Say. Bar Harbor; Salisbury Cove; Stations 

 F129 and F137, June 14-Aug. 10. 



Tbichocorixa Kirkaldy (Corixa Geoff roy) 



T. vERTicALis Fieber. Large numbers of them were in the 

 brackish pools at the Narrows Aug. 1934 but I have not 

 seen any since. 



NoTONECTiDAE. The Back-swimmers 

 NOTONECTA Linnaeus 



N. UNDULATA Say. A common and widespread species of vari- 

 ous shades. Station F137 was very productive. 



N. iRRORATA Uhler. Penikese; Station F212, July 25-31. 

 Scarce. 



Nepidae. The Water Scorpions 

 Eanatra Fabrieius 



R. FUSCA Pal.-Beauv. {americana Mont.). In various small 

 ponds where there is plenty of vegetation. Pond near Town 

 Hill; Stations F168 and F212. 



