108 INSECTS WHICH PREY UPON AGRICULTURAL PLANTS. 



the thighs have a small tooth beneath. Partridges are very fond 

 of the maggots, picking them out of the galls. 



Ceutorhynchus assimilis (the Turnip Seed Weevil). — It 

 deposits its eggs in the pods of the seeding turnips and other 

 cruciferous plants, the maggots devouring the germs, and thus 

 doing much damage when the crop is grown for seed. The 

 beetle itself is black, but clothed with very fine hairs, which 

 give it a greyish appearance, and it is about three sixteenths of 

 an inch long, including the beak, which is slender and arched. 

 It may be seen running about on turnip leaves, and w^hen 

 touched falls down until the danger is over. 



Ceutorhynchus contractus (the Charlock Seed Weevil). — This 

 insect is nearly allied to the preceding, being similar in form 

 but much smaller in size. It is believed to form small galls in 

 the larva state on the roots of charlock, but the beetles attack 

 turnips as w^ell, eating the seed before brairding, and the coty- 

 ledon leaves after. Much of the damage done to the turnip 

 crop during the past season was by this insect, and not by the 

 ordinary " turnip-fly " at all. 



The following are several other pests of farm crops, w^hich, 

 though not insects, may be conveniently described along with 

 them : — 



Julus Londinen^is (the London Snake Millipede). — So called 

 from having been first found in the neighbourhood of the 

 metropolis. It is usually about one inch long, of a slate or 

 leaden colour; the legs are of a dirty white colour, 160 in num- 

 ber, in pairs on each side, each segment having two pairs. It 

 grows for two years before the organs of generation are developed, 

 and changes its skin five times. It is at first only provided with 

 six legs, and an offensive liquid is secreted from its body. It 

 lives on the roots of grain and green crops. Another variety is 

 the J'uhis 'pulchdlus or " Beautiful Snake Millipede." This is 

 about half an inch in length, of a pale ochreous colour, and with 

 a double row of bright crimson spots down each side. It turns 

 purple when dead. 



An ally of the above is the Flattened Millipede (Polydesmus 

 com])lctncttus) — one of the "Meg-many-feet" of the country. 

 This variety is of an orange or pale lilac colour, the segments 

 not being so numerous, but more distinct than the last. The 

 respiration is by "tracheee " or breathing-tubes, like that of 

 insects. There is no distinct Hne of demarcation between the 

 ' thorax and abdomen ; one pair of feelers ; mouth masticatory. 



Limax agrestis (the Milky Slug). — This animal needs no 

 description, as it is too well known. It is always of a whitish 

 or ashy colour. The true snails are provided with a shell, but 

 in this and tlie black slug, the only approach to it is in the 



