NoVEMBEB 1, 1694.] 



KNOWLEDGE. 



247 



the insect, rearing itself perfectly erect, and flourishing 

 its four front legs in the air, goes hobbling along on its tripod, 

 prodding its pointed body into the ground at every step, 

 ■while the legs bend like springs as it does so. Such a sight 

 may often be seen in the proper season on damp grassy 

 spots where the insects are plentiful, and they may be 

 watched with ease, for there is no fear of their shyly 

 retiring from observation, since they are far too intent on 

 their work to notice the presence of an intruder. 



When a suitable spot has been found, the ovipositor is 

 plunged into the ground and kept there while several eggs 



FiCr. 3. — Attitude of female Daddv-loiiglegs, wlien ou an 

 egg-laying expedition. 



are passed down into the hole. Sometimes, however, they 

 are laid amongst the grass or leafage close to the surface 

 of the ground, instead of being buried. As many as three 

 hundred eggs may be produced altogether by a single 

 female, but they are not all laid in the same spot, and it is 

 difficult to say what determines the number to be included 

 in a single set, unless it be the proportionate abundance 

 of food. The difi'erent groups, however, are often laid 

 tolerably close together, and in bad visitations this is 

 necessarily the case. Kirby and Spence record an instance 

 in which the immense number of two hundred and ten 

 grubs were found in a square foot of turf during a terrible 

 plague of them in Holderness in the year 1818. 



From the black eggs are hatched thick, greyish, footless 

 grubs, with an extremely tough skin. They are generally 

 known to gardeners as "leather-jackets," or simply as 

 " the grub." They are soft and flexible, but so tough that 

 it is difficult to damage them by any means short of 

 absolutely cutting the body in two or tearing it to pieces. 

 This feature they possess in common with another sub- 

 terranean grub, which the reader will be careful not to 

 confound with the " leather-jacket," viz., the celebrated 

 wireworm, or grub of skipjack beetles ; this creature 

 differs in being thin, hard, inflexible, and of a yellow 

 colour. Though the " leather-jacket's " head is large, it is 

 not generally seen, as it is almost entirely imbedded in 

 the following segment. It is furnished with powerful jaws 

 which arc forked at the tip. The entrances to the breathing 

 tubes are reduced to two openings placed at the tail end of 

 the body ; here are also some pointed hooks, which, like 

 the head, are usually withdrawn within the adjoining 

 segment when not in use. They are of assistance when 

 the grub works its way through the soil. 



This wretched grub is subterranean in- habits, and if it 

 does chance to come to the surface, it is only in the night 

 time, or under the shelter of some friendly stone or pile of 

 dead leaves. Its business underground is to devour the 

 roots of plants, and this business it discharges most 

 efl'ectually. It possibly does damage also by loosening 

 the soil round the roots as it works its way about. Its 

 diet certainly seems to suit it well, for it is usually found 

 in a very fat and flourishing condition. Its principal food 

 appears to be the roots of grasses, but it is by no means 

 confined to these. I have found it very destructive to 

 certain garden plants, especially to blue lobelias used as 

 an edging. Shortly after the young seedlings have been 

 bedded out, they begin to look unhealthy and droop and 

 wither. Frequently also the previously erect stems 

 fall into a sloping position and wither away. On re- 

 moving the soil from the base of the plant to investigate 

 the cause of its drooping condition, a fat " leather- jacket " 

 is found in the centre, just where the rootlets ought 

 to be ; the tenderer portions of these have all disap- 

 peared, and only the tougher and older parts are left, 

 while many of the stems are seen to be gnawed round 

 or cut completely through at the base, thus explaining 

 their prostrate position and withered appearance. In such 

 cases, unfortunately, one does not discover the enemy till 

 the mischief has been done, and it is too late to save the 

 plant. Of course, such damage is the more likely to occur 

 where the bed is bordered by a grass plot. 



This destructive work is carried on by the grubs more 

 or less continuously during the summer months, from May 

 to July, and sometimes they may be found at work even 

 as early as February. During this time, far more than 

 what is actually devoured is caused to perish through the 

 removal of the roots. But it is only fair to remark that 

 some slight plea of defence may be advanced, which will 

 perhaps serve to take the edge ofl' the charge of wholesale 

 destructiveness which must otherwise be made. In eating 

 the roots, the grubs inevitably swallow a good deal of earth, 

 and, in fact, to such an extent is this the case, that so 

 careful an observer as Eeaumur thought they lived upon 

 this rather than upon roots ; hence they may perform to 

 some slight extent a service similar to that carried out by 

 worms, in the passing of earth through their bodies. 

 Towards the end of summer the grub becomes a chrysalis 

 while still buried in the soil. It now appears as a long, 

 brown, narrow object, which shows indications of the parts 

 of the future fly. The legs are present, but bent up at 

 what will ultimately be their joints, in three parts, which 

 lie parallel to one another on the under side of the head 

 and thorax. The thigh points towards the tail, then the 

 shank is bent back upon this, and finally the tarsus, or 

 foot, points again in the direction of the tail. By this 

 arrangement all the tarsi are made to lie on the outer side 

 and to terminate at about the same level. Of course, these 

 legs, being enclosed within the membranous skin of the 

 pupa, are quite useless for purposes of locomotion. 



When the fly is fully formed and ready to make its 

 appearance in the air, the chrysalis works itself up through 

 the soil to the surface by means of certain spines on the 

 abdomen, which point outwards and slightly backwards. 

 Using these somewhat as climbing irons and props, it 

 works its way upwards step by step until all the fore part 

 of the body is above ground. Its legs are now free from 

 the soil, and when drawn out of their sheath, after the 

 splitting of the skin, can be used to assist in extricating 

 the body. But in order to give purchase to the struggling 

 insect in its endeavours to get free from its case, the lower 

 part of the chrysalis remains imbedded in the ground, and 

 the body is withdrawn from the shell, which is left 



