THE ACARINA OR 3ITTES— BANKS. 



63 



117.— CiLLIBA HIRSUTA, FROM 

 BELOW. 



4. Leg I without claws 5 



Leg I with claws 6 



5. Legs with scale-like hairs; dorsal and ventral plates separate and <Iistin(t. .Pohjaspis 

 Legs without such hairs, no ventral plate VroRcius 



6. Dorsum covered by one plate fused to the ventral plate; peritrenie sinuate; ante- 



rior coxa? contiguous Diwjclius 



Dorsum with several plates, n(^t fused to the ventral jilates; i»eritrenie l)ut little 

 curved; anterior coxae separate TracJnjtes 



Our species of the family have been but little studied, and only 

 three of the above genera are known in this 

 country. 



Species of Urojxxla are frequently found 

 attached to various beetles. One of these 

 is connnon on the Colorado potato beetle, 

 and it was formerly supposed by many eco- 

 nomic entolomolo- 

 o-ists that the mites 

 fed upon the beetle. 

 It has lately l)een 

 claimed that some 

 species feed on bac- 

 teria and small fungi. The species are very 

 numerous; some are smooth, others hairy; 

 nearly all of a red-brown fawn color. The 

 species of Ghjphopais have usually been found 

 in ants' nests, and seem to live on good terms 

 with the ants, although their exact status is 

 not known. Irroseins and /^///^/.sy>/'.v are leased 

 on a few forms, and not well known. 



Tt'dclnjtcs contains two or three pyriform 

 species found in moss; the genus was formerly 

 called Celxno. CllUha (formerly known as 

 Dhcopomci) is similar in appearance to Urop- 

 (tda. Some species have been found in moss, 

 but others occur parasitically upon ants, at- 

 tached to the thorax or abdomen. One of our 

 species, (J. circuJarix Banks has l)een found 

 thus fastened to the thorax of Ci'einaxtocjustrr 

 lineolata. Another species, C. Jih'suta Banks, 

 was taken upon a species of Lax hi x in Arizona. 

 The relations existing between the Dlsropoma 

 and the ant has formed the subject of several 

 recent investigations, both by Wasmann and by Janet. The mites 

 which cling to the abdomen of the ant do not seem to be disturbed b}^ 

 the ant, but if a mite was placed on the ground of the nest it was 

 seized and destroyed by the ants. The mites bite through the soft skin 

 situated between the seofments, and thus draw blood from their hosts. 



Fig. 118.— Dinychus ameri- 



CANTJS. 



