ISLE OF WIGHT DISEASE IN HLVE BEES— ACARINE DISEASE, 209 



about one-third of the body width from the margin, and slightly in front of the 

 dorsal furrow. Behind these are two pairs at about the middle of the body, 

 one pair near the margin and the other in a nearly direct line behind the second 

 pair. A pair arises nearly opposite the origin of the third pair of legs ; behind 

 these are two pairs constituting an almost straight transverse row, closely followed 

 by a final pair close to the hinder end of the body, and separated by about a 

 third of the width. 



Tracheal System. — A pair of stigmata opening dorsally occurs anteriorly close 

 to the base of the gnathosoma. From these the more dorsal and anterior portions 

 of the tracheal system pass backward as a pair of curving, slender tubes, which 

 cross each other at the level of the anterior limbs. These pass ventralwards 

 curving inwards toward each other, and again outwards towards the bases of 

 the posterior limbs. 



Legs (text-fig. 2). — The anterior pair is jointed, and terminates in a single hook, 

 with circular sucker in addition. On the penultimate segment upon the dorsal side 

 there is a sensory spine-like organ — "riech-haar" of Otjdemans. The second pair 

 also carries a similar spine and ends in a double claw and sucker. The third pair 

 of legs resembles the second, but a "riech-haar" is absent. These limbs arise near 

 the margin and are directed outward and backward, and usually lie clear of the body 

 for the greater part of their length. The fourth pair of legs, which arises closely 

 behind the third pair, exhibits distinctive features. In contrast to what is usual 

 in other species, instead of being long and slender, this limb is moderately stout at 

 its basal segment and slender beyond. But the whole limb consists of only two 

 segments and is much reduced in length. Upon it are four hairs, two of which are 

 terminal and of considerable length. One of the remaining two arises nearer the 

 base, but is usually seen along with the terminal hairs, forming a group of three 

 projecting beyond the body (text-fig. 2, h). 



Immature Female. — This differs in size and general shape, being more trun- 

 cated behind (fig. 9). 



Length of body from "13 to "15 mm. 

 Width „ „ -08 to -09 mm. 



Adult Male. — The adult male is smaller than the female and more truncated in 

 form behind. 



Total body length '11 to '15 mm. 

 „ width "06 to "08 mm. 



Dorsally, it appears to consist of three segments, besides the gnathosoma. Only 

 five pairs of hairs are present, all placed slightly inward from the lateral margin, 

 and nearly equidistant along the side. On the ventral side the following features 

 are observable. The transverse furrow behind the second pair of legs is well marked. 

 There are no longitudinal epimeral grooves such &s, are prominent in most free-living 



