THE ACARINA OR MITES. 



115 



' recorded that one species {E. berghi Jensen) lives parasitically in the ogg capsule of a 

 horse-leech in Denmark. From the egg hatches the six-legged lan^a, which soon molts 

 into the nymph. The latter devours the embryonic leech and then passes into a hypo- 

 pus. This escapes from the capsule, 

 attaches itself to an insect, and, on 



I reaching suitable locality, molts into 



: a full-grown nymph . The latter cuts 

 through the capsule, enters, and 

 there transforms to the adult mite. 

 Here reproduction takes place, and 

 the life cycle begins anew. One 

 species, H. tarsalis Banks, has been 

 found in the nests of rats in Cali- 

 fornia, and the hypopial form at- 

 tached to the rat fleas. 



The gen as Glyciphagus does not 

 appear to be as common in this coun- 

 try as in Europe; possibly owing to 

 their minute size they have not 

 been collected. A few species, of 

 rather modest appearance, arc 

 known to me. One (fig. 232) has 

 long plumose hairs on the body, and 

 was found in seeds. In Europe sev- 

 eral species appear to be common in 

 houses and other buildings. Some 

 species are pro^ided with many 

 broad scalelLke hairs. In all the 

 forms the skin is finely granulate, 

 which character serves to distinguish 



Fig. 237 .—RhizogJypMs rliizovTiagus. (Author's illus- 

 tration.) 



it from all other tyroglyphids. The original species of the genus (as indicated by 



the name) and some others have been found in sugar. The mites sometimes spread 



to the hands of those handling such materials, and produce a skin disease known 



as ''grocer's itch." Michael has described two remarkable forms which he discovered 



in the nest of the mole. The body is broad, flat, and the margins crenulate and 



provided with spines. They do not 



occur in deserted nests, but their 



relation to the mole is unknown. 



They may, perhaps, form a distinct 



genus. 



The curious genus LabidophoriLS 



(fig. 233) has not been found in this 



country. The genus was based on a 



hypopus that is found attached to 



moles. Michael has worked out its 



life history, finding that the adult 



is muchlike Glyciphagus. The male 



has several curious comb like projec- 

 FiG. 238. — Rhizoglyphus hyacinthi, side view. (Original.) , . ., ^, , • i .- ^i i ^ 



tions from the under side of the first 



and second pairs of legs and some plumose bristles on the other legs. The adult 



lives in the nests of moles. Another species occurs in the nests of squirrels and 



also on the squirrel. Chortoglyphus is known from but one species in this country, 



C. gracilipes Banks, which was found in tobacco infested by the cigarette beetle. The 



European species has been taken from old hay. 



