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REPORT 108, U. S. DEPAETMEXT OF AGRICULTURE. 



TVo species, T. xylocopae Donn. (fig. 243) and T. osmiae Dufour, are common in 

 Europe and both have been recorded from this count^^^ The adult of one species 

 was found in the bee's nest and has much the appearance of the ordinary- Tyroglyphus . 



Some species of Trichotarsus occur in the basal al)- 

 dominal cavity of certain old-world bees (Koptortho- 

 soma) in association with the Paragreenia mites. 

 They probably do not feed on the bees, and their 

 relations to the Paragreenia are unknown. Oude- 

 mans has divided the genus into se^-eral on ^•e^^' 

 slight characters. 



The European genus Hericia is allied to Trichotarsus 

 and is found in the sap flowing from wounds on trees. 

 The European genus, Fusacarus, has a hard l:>ody and 

 the mouth parts are not visible from above. It has 

 been taken from moles' nests. The genus Hyadena 

 (Lentungula) , found on marine algae in England, Heli- 

 goland, and the Antarctic, is peculiar in having a 

 slender hook-tipped process near the tips of tarsi I 

 and II. A new genus and species has been recorded 

 as injurious to the roots of the vine in Italy {Uetero- 

 glyphus vitium Foa), but it appears to be close to 

 RMzoglyphus, and probably is a s^-nonym of it. 



Family CANESTRIXIIDJ.. 



This family, named in honor of the famous Itahan 

 acarologist, Giovanni Canestrini, comprises only a 

 few forms of ver\^ small size and . parasitic on insects. 

 They are related to the Sarcoptidae and also appar- 

 ently to the T^Toglyphidae. The body is entire, 

 although there is usually an indication of the transverse furrow on the dorsum. 

 The legs are rather short, with few hairs, and terminate in a sucker like that of tlie 

 Listrophoridae. The mouth parts are small and concealed in the rostrum; the man- 

 dibles generally chelate. The palpi are simple 

 and filiform. There are sometimes two suckers 

 on the liind part of the venter for copulatory pur- 

 poses. The dorsum bears a few hairs or bristles 

 and some longer ones at tip. Their life liistory 

 has not been investigated. Most of the species 

 occur on beetles, some under the elytra. One 

 species that has been recorded from tliis country, 

 Hemisarcoptes coccisugvs Ligni^ros (fig. 245), lives 

 among the eggs of Lepidosophes ulmi L. and other 

 scale insects. It feeds on the eggs or on the scale 

 and is thus very beneficial, but unfortunately not 

 common enouirh materially to reduce the num- 

 bers of these insect pests. It was first descril:)ed 

 from Ohio as Acarus malus by Shimer and also 

 occurs in Europe. 



The principal genus is Canestrinia (fig. 244), 

 of which various species have been described 



in Europe and Africa. Several undescribed species occur on lamellicorn and other 

 beetles in this country. A large form, C. blattophaga, occurs commonly on cock- 

 roaches in Central America. I have described a remarkable Mexican species 



Fig. 243. — Trichotarsus xylocopae: 

 Nymph, and claw enlarged. (Au- 

 thor's illustration.) 



Fig. 244.- 

 bolow 



■Cancsirinia sp.: Female from 

 . (Author's illustration.) 



