32 British Vegetable Galls 



Within the last few years elaborate researches have been 

 made into the economy of these creatures by Dr. Alfred Nalepa, 

 of Vienna. To his writings all gallists are indebted for a more 

 extended knowledge of gall-mites. He has determined and 

 named 227 Continental species, and is familiar with about 

 twenty others ; some thirty of these are at present known in 

 Britain, and doubtless dozens more will in time be discovered. 



He has established various genera, families, and sub-families, 

 the gall-producers among them being Eriophyinse, Phyllocoptinje, 

 and seven others. These creatures vary in size from 250 /i long, 

 60 /x broad in thee?, and 310 /x long, 60 fi broad in the ?, of 

 Eriophyes mentJiarins, which is the largest known species, to 

 90 /x long, 30 /i broad in the c?, and 100 /a long, 37 /i broad 

 in the ? of E. pai-vulus, a difference in the c?c? of 160 /it long. 

 30 /u. broad, and in the ? ? of 190 /x long, 23 /i broad. The 

 largest species is scarcely visible to the keenest naked eye. 



The entire creature is long and cylindrical, of a vermiform 

 shape, the head being fused to the thorax, and that in turn to 

 the abdomen. 



The head and thorax are hidden from above by a hemi- 

 spherical, shield-like plate, bearing upon it characteristic sculptural 

 markings, which form important features in the nomenclature. 

 The head is slightly bent in a downward direction, and is 

 pointed, or snouted. The mandibles are needle-shaped. The 

 maxillae are three-jointed, and are used as antennae. 



The abdomen is greatly elongated, diminishing in size 

 towards the tail ; it is ringed all round. The number of the 

 rings varies from 40 in E. gotiiothomx to 95 in E. buxi. Several 

 (generally seven) pairs of long, stiff bristles, or setiv, are always 

 present on the body, and they appear to serve the purposes of 

 organs of touch. The tail is divided into two semi-circular flaps, 

 which can be closed together at will and withdrawn ; it bears 

 at its extremity one pair of whip-like bristles much longer than 

 the other pairs. The anal opening is close to the flaps. The 

 generative organs are partially external, situated on the ventral 

 surface of the abdomen, close to its union with the thorax ; 

 they are known as epiandrhwi for the $, epigynium for the ? . 



The mites have no special respiratory or circulatory organs. 

 The exchange of gases takes place through the body. Nor is 

 there any organ like a heart ; the fluid, therefore, which is 



