THE ACAEIXA OR MITES. 



21 



Fig. 10.— Cephalothorax of 

 Bimichaelia. (Original.) 



Of the Alicliinae the two genera are distinguished as follows: 



1. Mandibles long and slender; no eyes Bimichaelia. 



Mandibles stout; eyes present Alichus. 



Alichus (fig. 9) and Bimichaelia (fig. 10) are pale or reddish minute species, with 

 short legs. They occur in moss, or damp situations. Bimichaelia has been taken 

 in Oregon. They are remarkable because of the distinct 

 indications of abdominal segmentation. Sebaia is similar 

 to Bimichaelia. Of the Eupodinae there are many genera, 

 the principal of wliich may be tabulated thus: 



1. Legs extremely slender, front pair much more 



than twice as long as body; Mnd femora 



somewhat tliickened Linopodes. 



Legs not much longer than body 2 



2. Anal opening on the dorsum ; last joint of palpus 



very short; patella of legs long; mandibles 



small Notophallus. 



Anal opening on venter 3 



3. A rounded median tubercle on front margin of body; mandibles very large; 



liind femora not thickened Rhagidia. 



No such tubercle ; mandibles smaller 4 



4. Hind femora very much thickened, front legs much longer 

 than others; last joint of the palpi slender Eupodes. 



Hind femora not or barely tliickened 5 



5. Last j oint of palpus shorter than preceding; patella of legs 

 elongate 6 



Last joint of palpus longer than preceding; patella of legs 



very short Tydeus. 



6. Dorsuni of cephalothorax with a median sliield; color 

 pale; no eye-spots; tarsi shorter than tibise Ereynetes. 



Dorsum of cephalothorax ^vithout a sliield; color dark or 

 reddish; an eye-spot each side; tarsi usually as long 

 as tibiae Penthaleus. 



Fig. W. — Noto-phal- 

 lus, dorsal view. 

 (Original.) 



Our one species of Linopodes (fig. 12) is a very pretty pale 

 yellowish or reddish mite, with some wliite marks; one on the back 

 is in the form of a T. It is common on the ground under pieces of 

 wood, bark, etc., that have lain there some time. The first pair 

 of legs is used as feelers. Usually the mites walk slowly, but when 

 disturbed run very rapidly. We have several species of Eupodes 

 (fig. 15), all more or less marked with red. The common one, 

 E. variabilis Banks, is found in the same places as Linopodes. 

 Another species occurs on the seashore between tide marks, and 

 one is found in caves. 



The species of Notophallus (fig. 11) are blackish, with a red 

 spot above, and red legs. They occur in damp fields, under 

 stones, or in moss. Species of Notophallus have been found to 

 be injurious to young plants, the mites sucking the leaves, and frequently causing 

 the death of the tiny plants; one form is very injurious in the Southwest. Species 

 of Penthaleus have a similar habit, and one in South Africa is known as the "earth 

 flea." Several species of Tydeus (fig. 14) are known from the United States. 

 T. gloveri Aslimead occurs on orange leaves in Florida, and feeds on the young and 

 eggs of scale insects {Lepidosaphes spp.). It is pale reddish or yellowish in color 

 and lias a subpyriform body, with rather short legs. Moniez has described a 

 species of Tydeus {T. molestus Moniez) as attacking man, much on the "red-bug" 

 style. Rhagidia is a remarkable genus. The species are pale or whitish in color, 

 and occur under damp, fallen leaves and on moist soil. It is much larger than 

 the other species of this family, and sometimes fully 1 mm. long. Ita structure 

 is in many ways very similar to that of certain Solpugida and suggested to Thorell 



