382 Annals Entomological Society of America [Vol. XIII, 



A more careful examination of the microscopical structures 

 reveals to us, however, that the species can be easily separated. 

 For this purpose Berlese has already used; size, the presence or 

 absence of the eyes, variations in the relative lengths of the 

 front tibiae and tarsi, the ratio between the length and breadth 

 of the front tarsi, and to a limited extent the nature of the 

 body setae and a few other structures. Of these characters the 

 selection of size appears to be rather unfortunate, as there is 

 not only a remarkable uniformity in size among some of the 

 adults, but the nymphs, which are smaller than the adults, are 

 so easily confused with the latter. The use of the ratio existing 

 between the lengths of the front tibiae and tarsi is good and in 

 this paper will be expressed by taking the length of the tibia as 

 unity. The following characters should be added to those given 

 by Berlese as being of much importance in specific diagnosis: 

 The structure and shape of the crista, especially the expanded 

 portion, or pseudostigmatic area; the position, size and structure 

 of the sense hairs, or pseudostigmatic organs; the structure of 

 the body setae, especially should it be noticed whether the 

 barbs extend to the tip or not, their relative length when 

 present at the tip, and also the thickness of the seta at its tip. 



THE "AKAMUSHI" OR " KEDANI " MITE. 



Through the generosity of Dr. Miyajima, the writer has 

 examined a good series of the adults of the "kedani. " In 

 general appearances these specimens are almost exactly like 

 our Trombiculas. However, when we examine those characters 

 that alone are of specific importance, we find that the Japanese 

 Trombicula is quite distinct from both our species. A descrip- 

 tion of the "kedani" adult follows in which only those char- 

 acters that are of specific importance are given. 



Trombicula coarctata Berlese. Color of alcoholic specimens almost 

 white, but live ones are "light reddish ochre" (Miyajima and Okumura). 

 Body well clothed with strongly pectinate, whitish setae, showing a 

 tendency to be grouped in longitudinal rows. Cephalothorax tri- 

 angular in outline. Eyes wanting, also vestiges wanting. Crista 

 extending for the whole length of cephalothorax; carina straight and 

 extending from the anterior end of crista into the pseudostigmatic 

 area; posterior lobes of this area more or less angulate and situated 

 directly behind the pseudostigmatic pores. Pseudostigmatic organs, 

 or sense hairs, delicate, about as long as the crista and each provided 

 with a few delicate barbs on the distal half, the nimnber of barbs present 



