1920] Ewing: Genus Tromhicula Berlese 385 



After rearing the adult of the "kedani" mite and demon- 

 strating the nymphal characters in that species, Dr. Miyajima 

 came to the conclusion that T. minor was only a nymph of T. 

 mediocris. A careful study of the nymphal characters as given 

 by Drs. Miyajima and Okumura certainly lends weight to 

 Miyajima's opinion. Of special importance is their demonstra- 

 tion that the "kedani" nymph has only two palpal spurs, while 

 in the adult there are four. If we grant the synonymy of these 

 two species, the name minor has precedence over mediocris 

 because of priority. This is unfortunate, as mediocris is one 

 of the largest species of the genus, yet according to the applica- 

 tion of the priority rule, loses this name to become minor. 



T. minor (mediocris) Berlese is found outside the East 

 Indies as was shown by Drs. Kitashima and Miyajima, who 

 received material from Formosa, sent by Herrn Hatori. In 

 their extended paper, "Studien ueber die Tsutsugamushi, 

 Krankheit," they give an excellent figure of minor {mediocris) 

 and make comparisons between this species and the adult of 

 the "kedani" mite, held to be coarctata. 



In the orient then we have, as far as is known, two Tromhi- 

 cula species, T. coarctata and T. minor (mediocris). One of 

 these is known at present in the orient only from Japan, the 

 other from Java and Formosa. It may be added that T. minor 

 has the body clothed with shorter, and colored setae, which are 

 of about equal length over all of the dorsal part of the abdomen, 

 while T. coarctata has longer and colorless hairs on the dorsum 

 of the abdomen, and those around the posterior margin are 

 much longer than those on the shoulders. 



OUR TROMBICULAS. 



As in the orient, so in the United States we have two Trombi- 

 culas. One of these was described by the writer as T. splendens 

 in 1913, from Wisconsin, and the other was discovered during 

 the summer of 1919 in Virginia and Maryland. T. splendens 

 resembles T. coarctata in having the long, colorless body setae, 

 which are much longer on the posterior margin than on the 

 shoulders, while our other species resembles Berlese's minor in 

 having the shorter, colored and almost uniform body setae. 

 The former species is here described : 



