A FoRKKix Invasion of England 307 



fully expniulcd, their jointed lc<4s weak and .i^rosij^y. 

 But after a time, as they hieatlie oi" inflate them- 

 selves with air, all these parts j^row fuUei-, lighter, 

 and harder. The Hessian lly in this predicament 

 waves her winj^s to and fro several times across 

 her back ; and in about a quarter of an hour 

 they have plinniied out fully, so that she can 

 soar away on hei- mairia_L;e-tli^ht to meet her pro- 

 spective aOrial husband. As for ihe tiny silveiy 

 shroud OI- deserted pupa-case, it is left protrudinj^ 

 from the stem of the barlev. 



This that 1 have i^iven you is the history of a 

 successful and fortunate ily ; but not every indi- 

 vidual of the species is quite so lucky. As in the 

 case ot the moscpiito, natine at times makes not a 

 few failures. Sometimes the flies have insuperable 

 difficulty in fieein.i4 th.emselves from their articu- 

 lated coverings ; sometimes they break or spoil 

 their le.L^s or win^s, and become helpless cripples. 

 Yet so strong is the impulse of everv species to 

 fill the world with its like that sometimes, says 

 Mr. Enock, even these pool- maimed insects will 

 manage to crawl to a proper food-plant, and will 

 lay their e_^^s on it bravely like their more fortu- 

 nate sisters. He noted one crippled female which 

 in spite of its feebleness was eiiflity times over a 

 happy mother. This is u^uallv the case with such 

 small insect pests ; their life consists, indeed, of 

 two things only, eating their way to the winged 

 stage, and then laying as manv eggs as possible, to 

 do like damage in the next generation. 



Three or four hours after emerging, when they 



