INJURIOUS INSECTS. 



* ' Camponotus Pennsylvanicus " and "Formica rufa." 



Carpenter Ant and Mound-building Ant. 

 (Ord. Hymenoptera : Fam. Formicid^.) 



In the preceding Report of this series (Eleventh), one of the large ants, 

 Camponotiis herculaneus var. Fdtinsylvaniais, is represented as sometimes 

 entering dwellings from nests built outside near the house. In one instance 

 mentioned by Dr. Riley, a fine old homestead was so overrun with it that 

 it was on the point of being sold, when the source of the infestation was 

 discovered in a large nest of several feet in diameter in the back yard. 



In all probability the above infestation as cited by Dr. Riley was 

 erroneously referred to C. JLerculaneus. Rev. Dr. H. C. McCook, of 

 Philadelphia, who has made special study of the habits of our N. Ameri- 

 can ants, has modestly questioned the statement in a recent letter received 

 from him : — 



" I think that I may venture to question the statement respecting 

 Camponotus Pejinsylvanicus on page 113. I am reasonably familiar with 

 the habits of this species, and have never known an example of a nest 

 made in the earth, as implied in your statement. It is a carpenter ant 

 exclusively, and lives in trees and timber. I suspect, therefore, that a 

 mistake must have been made in the species. I have occasionally seen 

 the Pennsylvania carpenter ant in houses, but as a rule, it is not inclined 

 to such resorts, and I very much doubt if it could have proved a house- 

 hold pest. 



" I make the above statement with some degree of confidence, even 

 though you quote Dr. Riley for your authority. However, if Mr. Theodore 

 Pergande endorses the species, I suppose I should waive my objection, 

 as he is well acquainted with the species of our American Ants.' ' 



Dr. McCook has also indicated another error made by me, on page 

 115 of the Report cited, where Formica rufa is given as the " not improb- 

 able " annoying occupant of the soil of a lawn on the south side of Long 

 Island, which " during the summer is alive with ants," and also the arti- 

 ficers of large mounds seen by me in the Catskills and in the Shawangunk 

 range at Lake Mohonk. He writes as follows : 



" You refer to our American mound-making ants as Formica rufa. 

 That is a blunder which I made when I first published an account of the 

 habits of these species in the Transactions of the American Entomological 



