The Phytoptus of the Vine. By Prof. Giovanni Briost. 187 
the belly. The first pair of the latter are placed between the ninth 
and twelfth ring (counting from the side where the head is), the 
second pair between the twentieth and twenty-second, the third 
pair towards the thirty-eighth ring, and the last pair invariably at 
the last but five rings. The hairs of the first dorsal pair are 
generally upright, diverging, and turned down at the end. The 
hairs of the last pair are nearly parallel with the axis of the body, 
turned towards the anus, the shortest and the closest placed towards 
one another (f, in Figs. 2,5). Landois, however, counts on the 
belly only six or seven large bristles; and Sorauer on the Phytoptus 
pert counts also six pairs, only slightly differently placed, as I 
found them on the Phytoptus vitis. 
The legs, colourless and nearly transparent, seem to be com- 
posed of six joints; the first, by which the leg is inserted on the 
thorax, corresponding with the coaa of insects, carries always a 
long bristle (Fig. 18); the second, which is the longest and most 
robust of all, shows two ring-like elevations, on the side of one of 
them being attached a second bristle; then follow three rather 
short divisions, the second last having a third bristle or hair 
pointed forward, and of such length as almost to reach to the 
extremity of the joint, which forms the fifth division, and on this is 
_ Seen a kind of strong and pointed style in the centre, bearing five 
appendixes or lateral bristles, so as nearly to resemble the form of 
a feather. There is also a small cylinder (through a lithographic 
error in the Plate ending in a point) bent forward and downward, 
which covers, so to say, the feather or thorn, and seems to protect it. 
The small cylinder is a little longer than the feather, and larger 
(the average of three which were measured was 0° 0066 mm. length, 
0-00085 mm. diameter). The length of the legs in animals whose 
bodies measured on the average 0°90 mm. was 0°025 mm., and the 
diameter 0: 00225 mm. at the coxa. 
Neither description nor drawing given by Sorauer of the tarsus 
of the Phytoptus pir correspond with those of the Phytoptus vitis 
described in the foregoing, and also drawn by Landois, who, how- 
ever, changes the small cylinder into a bristle. The legs are 
compressed at the sides, and therefore if seen sideways appear 
larger than seen in front. 
Landois distinguishes in the legs three divisions only, but says 
that there are in the middle one (corresponding to our second one) 
two slight elevations, and in the third, two or three kind of loops 
or ring-like indentures. I agree that the first ones may be simple 
elevations, but the second ones appear to me true divisions of parts, 
and because of them I count five, which added to the tarsus, form 
therefore six parts or divisions for each leg. 
The animal walks very quickly notwithstanding the distribution 
of the moving organs, which is little suited to the shape of the 
VOL. XVII. P 
