THREE NEW CHIGGER MITES OF THE GENUS TROMBIC- 

 ULA FROM PANAMA, WITH A KEY TO THE KNOWN 

 ADULTS OF TROMBICUI.A OF THE NEW WORLD 



By H. E. EwiNG 



Bureau of Entomology, United States Department of Agriculture 



Three new species of the genus Tromhicula were contained in a 

 small collection of mites sent in for identification from Panama, by 

 L. H. Dunn, medical entomologist of the Gorgas Memorial Labora- 

 tory, Ancon, Canal Zone. Two of these are represented by adult 

 specimens taken from caves. These cave species are blind, and in 

 addition one of them differs from any known described species in 

 having the tarsal claws of the first pair of legs trifurcate. At first 

 the writer was inclined to establish a new genus for this species, but 

 he decided that it probably represents a form already known in the 

 larval stage. 



Until many more rearings are made it will be best to use larval 

 characters for our genera of chigger mites, as less than one species in 

 10 is known from the adult stage. Eventually, however, this process 

 will probably be reversed, and our genera of the Trombiculinae will 

 be based chiefly on adult characters. 



The known adults of Trombicula of the New World may be 

 separated by the following key: 



KEY TO ADULTS OF THE GENUS TKOMBICri>A OF THE NEW WORLD 



1. Claws of first pair of legs simple, not trifurcate 2 



Claws of first pair of legs trifurcate distally ; this pair not only 



much larger than the others but also much more sclerotized. 



trifurca, new species 



2. Eyes present and well developed ; setae of body but slighlly 



longer on posterior margin than on shoulders, and colored 3 



Eyes vestigial or absent; setae of body usually considerably 



longer on posterior margin than on shoulders 5 



3. Eyes with strongly convex corneas and situated far in front 



of base of dorsal groove ; length of adults, over 2 mm 4 



Eyes with corneas less convex and situated approximate, later- 

 ally, to expanded base of dorsal groove; length of aduUs 

 about 1 mm irritans (Riley) 



No. 2970.— Proceedings U.S. National Museum, Vol. 82, Art. 29 



175ST1— 33 1 



