114 Objects for the Microscope. 



Frequently our gooseberry trees are stripped bare by 

 hosts of these young Saw-flies in larvse ; they spin cocoons, 

 and remain coiled up in them all through the winter, re- 

 maining but a few days in the pupa state, and emerging in 

 May and June. 



CYPHEUS PYGM,fiUS, 



another Saw-fly. It will be most interesting to the farmer, 

 because its larva is very troublesome in the wheat and rye- 

 fields, especially in France, where it often destroys a great 

 part of the crop. The fly itself is black and yellow ; the 

 male, as usual, differs from the female in colour and size ; 

 that is, he is of a brighter yellow, and the wings clearer 

 and more iridescent ; hers are clouded, and the yellow of 

 her body and legs more ochreous. The larva is singular in 

 having no legs at all, but a kind of tube at the end of its body 

 with a telescope movement by which it progresses along its 

 tunnel, for it feeds in the stem of wheat or rye ; and its 

 history is interesting. The female Saw-fly may be seen in 

 a warm April day sawing a hole just beneath a knot in the 

 tender stem of the young wheat, and depositing one egg in 

 each straw. This is soon hatched, and forthwith the larva 

 begins to gnaw, with some exceeding strong though tiny 

 mandibles, the juicy inside cells of the stem, which of course 

 disturbs the economy of the plant, and prevents the upward 

 flow of all the nourishment which is needful for the growing 

 ear. As soon as it can it proceeds to grind away the in- 

 terior of the knot also and ascend the stem. As it grows 

 and thrives, the plant withers ; but in the month of July 

 begins to descend toward the earth, and a few days before 

 harvest-time it settles itself near the root of the wheat, cuts 

 the straw regularly round inside, so that it breaks off under 

 the first puff of wind, and the little creature spins a warm 

 cocoon and lays itself up for the winter, fat and happy, un- 

 less a certain little cousin, one of the Ichneumon-flies, has 

 found it out, when his life will not have reached this period, 

 or its mischief have been so fatal 



