Injurious Tipitlidcc. 95 



ground, ami caused complcic dcsuuciioii of beds of quite large size. 

 It is mainly in undislurlxjd ground that these insects ])ropagate, 

 esiK'cially when there is moisture, as in damp meadows, mai-shes, 

 and amongst the vegetation along dykes and ditches. The smaller 

 larvji» of P. maculosa occur most abundantly on light soils, but not 

 by any means entii*ely, for I have seen them in swanns during the 

 past year on clay land. They occur in hilly districts just as 

 abundantly as in low-lying mai-shy land, in light and heavy soil ; in 

 fact, they have as wide a distribution as the common Crane Fly. 



Tlie larvos of all these and other injurious species live throughout 

 the winter, feeding all the time, except when the gi-ound is frozen ; 

 they then pass deeper into the earth to escape the cold. Some .seem 

 to i-eiich maturity sooner than othei-s of each species, for it is not 

 infrequent to find adults of some of the species occuning over several 

 months, but the main brootl occm-s about the same time ; others 

 have two or more bi*oods in the year. (Jmss land and root crops 

 perhaps suffer more than anything else from the ravages of the 

 Leather-Jackets. The folloNnng instances may here l)e recorded. 

 In 181.'^, acconling to Kirl>y and Spence (" Introduction to Ento- 

 molog}'"), hundreds of acres of giass land were destroyed by 

 Leather-Jackets. In 1842 the marsh lauds by the side of the 

 Thames in the Isle of Grain were so completely destroyed l)y these 

 grubs that the gi-ound was bare. This occuned again in 1804 in the 

 same area. Tlie larvae, of course, difter in certain features in each 

 species. In genei-al fonn they are cylindrical, without any feet, with 

 a distiiK-t homy head, retractile, i.e., it can easily be drawn into the 

 .succeeding segments ; the posterior end is tnmc^ted and ends in a 

 numl>er of fleshy projections, so-called papilLi?, which vary in the 

 ditt'erent species. There are two respiratoiy orifices on the last 

 .segment. The mandibles are dentate and work transvei-sely, not upon 

 one another, but upon two other fixed pieces. They are not only 

 found living in roots, but also in rotting wixxl and even in water, 

 both salt and fresh. The pupai of these in.sects can easily \y(t dis- 

 tingufshed by their having two horn-like projections frem the head ; 

 the segments of the alulomen are encircletl more or less with spines, 

 csi>ecially l>eneath, and, like most of the nematocera, are* naked, that 

 is they are not en.shrouded in a puparial ca.se. This stage in the 

 i"oot-fe«Hling TiptUida is always found in the giound where the larvaj 

 have Ut'ii feeding, generally at .some little disUmoe from the surface. 

 Just l>efore the imago is reatly to emerge they wriggle |)artly out 

 of the ground, the alnlominal spines Iniing u.sed for this puq)ose; 

 usually alwut half the pupa projects al)ove the level of the earth. 



