68 FAUNA OF MAYFIELD'S CAVE. 



Order ACARINA. 



Family EUPODIDAE. 



Rhagidia cavicola Banks. 



Bryobia weyerensis PACKARD, Mem. Nat. Acad. Sci., iv, 1888, 42, pi. xi (Weyer's 



Cave, Virginia). 

 Rhagidia cavicola BANKS, Am. ; Nat., xxx, 1897, 1382, pi. x, fig. 3 (Mammoth Cave). 



Seen quite often and probably is fairly abundant although incon- 

 spicuous. It is about 1 mm. long. It is perfectly white and shows no 

 trace of eyes. In color, size and general appearance it very much 

 resembles the young of the thysanuran Sinella cavernarum. This mite 

 occurs in all parts of the cave in loose earth under debris or at decaying 

 organic matter where there is considerable moisture, and usually in 

 company with Sinella, for which I at first mistook it. It probably preys 

 upon this thysanuran and upon eggs and larvae of other cave animals. 

 Packard, according to Mr. Nathan Banks, took this species (probably) in 

 Weyer's Cave, Virginia. I have little doubt that it is generally distrib- 

 uted in Indiana caves, but has been overlooked because of its small size 

 and resemblance to Sinella. 



Other species of this genus live under dead leaves and in loose moist 

 soil. Another species of this family (Linopodes mammouthia Banks) is 

 described from Mammoth Cave, where it occurs in moist dirt (Call, 1897, 

 p. 382). Banks (1904, p. 13) says of this family of mites: 



Most inhabit the ground, but some are found on the leaves of trees. All are 

 predaceous and feed on various small insects or insect eggs. They seem to delight in 

 cold, damp places, and can be found in winter still active [among and under fallen 

 leaves. They are among the most common acarians in high altitudes and are also 

 frequent in caves, both of this country and of Europe, where their simple and primi- 

 tive structure is well suited to the conditions. 



Family TYROGLYPHIDAE. 

 Tyroglyphus sp. 



The Hypopus or migratorial stage of some Tyroglyphus occurred in 

 extreme abundance upon one of the flies in the cave (Leria latens) . 

 Specimens were sent to Nathan Banks, who replied as follows: 



The mites are the Hypopus or migratorial stage of some Tyroglyphus it is 

 impossible to tell what species. Probably it is new. Only a few species of Tyrogly- 

 phus are described from United States, and only one or two of these have been 

 connected with their Hypopus. The mites do not feed on fly. 



At times the mites are to be found upon nearly every Leria latens 

 taken and occasionally 30 or 40 are seen clinging to a single fly. The 

 mites are especially abundant upon the abdomen, but attach themselves 

 to all parts of the body of the fly. While so very abundant on Leria 



