326 



JOURNAL OF THE ROYAL TTORTTCULTFRAL S()C!1RTY. 



With the larva of the Hessian Fly the last skin is not thrown off, 

 but simply hardens and changes to a cbestnut-red. Tlie next change is 

 a liidden one, only to be I'evealed by tlie most cureful dissection and 

 examination by removal of the outer skin, when a pure white maggot 

 is found, having on the third segment a small forked ajiparatus known 

 as the breast boiie or anchor process, which, one entomologist asserted, 

 *' assisted the larva in obtaining its food," overlookmg the fact that the 

 anchor process did not develop until the feeding stage had been passed, 

 and between it and the stalk the hard skin of the puparium intervened. 



Arranging and fastening down a number of puparia in rows of ten, 

 with their heads down and in one direction (as in their normal position), 

 I dissected several in the first row, finding all the internal larva in 

 the same position, viz. heads down and mouths toward the stalk. The 

 next week T dissected part of the second row, with the same result. 

 Some weeks later I found one of the internal larva with its head up 

 and its back to the stalk ! Plow had it managed to reverse its position? 

 Continuing my examination of the larvae, I found one with its head 

 just on the turn, and closer examination showed that the forked and 

 free tips of the anchor process were driven into the skin of the puparium, 

 and, acting as a " scotch," prevented it from slipping down; the larva 

 then by mnscular effort moved its back down a very short distance, 

 pressing the reverse spines covering its back into that of the puparium ; 

 the anchor tips were then withdrawn and moved a slight distance higher, 

 the back again moved down, was "scotched," and so on, until by 

 repeated action of this wonderful contrivance the larva reversed its posi- 

 tion of head downwards and inwards to head up and outwards, with 

 only the thin leaf-sheath between it and the open air, to penetrate which 

 by the pupa was an easy task. In September these reversed larvfe 

 changed to pupae, and in a few days pierced the leaf -sheath and the 

 perfect Hessian Fly was liberated. In America the autumn wheat is 

 sometimes utterly ruined by the myriads of flies laying their eggs on 

 the tender blade almost before any stalk has grown, the larvae working 

 their way right down to the grain, and often changing to the puparium 

 stage inside the husk. Owing to the later sowing -in Great Britain,- 

 the crops escape tlie autumn attack, though young plants of self-sown 

 wheat are generally attacked. 



Such, then, is a brief life-history of the Flessian Fly, which, 

 partly owing to our climate and times of sowing wheat, does not appear 

 to feel comfortable in our country. I might mention that at the time 

 of its visitation I bred a very large number of parasites (fig. 117) from 

 the puparia gathered. I suggested the advisability of collecting large 

 quantities of the infected straw with the view of breeding vast numbers 

 of these natural checks and turning them down in the infested districts, 

 as they would do their appointed duty without the red-tape regulations 

 of those unacquainted wn'th their habits. This proposal of mine was 

 disregarded by those in authority; so I wrote to my friend the late 

 Professor 0. Y. Riley, United States entomologist, asking him if he 

 would like me to send some puparia containijig the parasites. He 



