118 ACAEINA OE MITES. 



brown in colour. On examining the buds in the winter we find 

 aU the acari safely housed between the scales : here they live 

 and breed. In the spring and summer they come out and move 

 over the bushes, taking up their position in new buds, which 

 they speedily deform. The ova are laid in the buds, and soon 

 hatch into mites very similar to the adults. In form the 

 Currant Gall Mite is elongated and dirty-white in colour. This 

 serious pest, which is spreading at a tremendous rate over 

 Britain, has not been checked in the least, because fruit-growers, 

 following incorrect advice, have been washing the bushes in 

 the winter, when aU the acari are safely housed and protected 

 from the acaricide. Eepeated summer washings with some 

 sulphur wash can alone have any appreciable, effect : this and 

 simultaneous handpicking might in a few years stamp out the 

 disease. One never sees this pest on the old varieties of Black 

 Currants. 



Linguatulidse. — There are two quaint genera of Arachnida 

 classed in the above family — namely, Pentastoma and Linguatula. 

 These curious worm-like Arthropods are parasitic, living in the 

 head and air-spaces of animals : they are more or less elongated 

 and vermiform in shape when adult, and have a distinct annu- 

 lated body. The mouth in the imago has no jaws, but is sur- 

 rounded by two pairs of hook-like legs. Like Acarina they 

 respire cutaneously. The one figured (fig. 48, e), Linguatula 

 tceniodes, is the commonest form, and may often be found in 

 domestic animals. At one time it was considered a tapeworm, 

 and unless carefully examined it certainly resembles some of 

 those worms. This acarus is dirty-white in colour, about three- 

 fourths to one inch in length in the male, somewhat larger in 

 the female. The female is often brown when fuU of ova. These 

 arachnida live in the nasal cavities, especially in the dog, and 

 there the female lays her eggs, which are sneezed out by the dog 

 along with mucus. These ova are eaten by sheep, oxen, rabbits, 

 and other herbivora, when the embryos (b) are released in the 

 intestines. By means of the median rod and curved hooks this 



