212 ARACHNOIDEA, 



CASE phora) have been ascertained to have a similar structure to that 



XIII. ^ ' 



of the young of the family to which the cheese mites belong 

 (Acaridae). They differ, however, in having no vesicle attached 

 to their feet, but they correspond with a portion of them, in having 

 a remarkable breathing apparatus, consisting of two tubes, which 

 open on the back part of the thorax, adding another to the different 

 variations in the mode of breathing in insects. This may be seen 

 in the accompanying woodcut of the cephalothorax of one of 

 them (Damgeus auritus). They are also furnished with curious 



appendages, such as plates or lamellje, 

 and differently formed hairs and tu- 

 bercles on different parts of the body. 

 They have no eyes. As already said, 

 for a long time the two singular breath- 

 ing apertures near the posterior angles 

 of the cephalothorax', were supposed 

 to be eyes, but now that the function 

 of sight has been found not to belong 



Head of Damaeus auritus, showing . .1 1 • 1 r 1 . a 



breathing pores and lateral projec- tO thCm, ttOtlimg ClSC Of thC natUrC Of 



tions. Copied from Nicolet. 



eyes has been discovered in their place. 

 They have tarsi bearing one, two, or three claws, according to 

 the species, but no suckers in any. 



Their development has been traced in many species from the 

 egg. The young larvae are hexapod when hatched. 



Authorities are not at one as to whether these insects should 

 be classified as hurtful or not. M. Nicolet, who has monographed 

 the Oribatidas found in the neighbourhood of Paris, says that they 

 never cause any damage either to man or the products of his 

 industry, but Mr. Curtis classes at least one of them as hurtful to 

 fruit trees. In one respect, in which he differs from Nicolet, he 

 certainly is right. Nicolet says that they are essentially vagabond 

 and solitary, inhabiting the moist mosses in forests and the sheltered 

 banks of waters, that they are found sometimes under stones resting 

 on a humid soil, and in decomposing vegetable matters, but that 



