TIPULID.E. NOTACANTHA. TANYSTOMA. 199 



C. destructor, is known in America under the name of the Hessian 

 Fly ; this attacks the lower part of the stem of the wheat. The 



FIG. 425. CK< 'IDOMVIA DESTRUCTOR, andC. TRITICJ, with the Larvae 

 of the latter feeding in wheat flowers, magnified. 



proper Tipulce, or Harry Long-legs, are the largest species of 

 the family. Their larva? generally live in the earth, in the rotten 

 parts of trees, &c., and many of them do great mischief by feed- 

 ing upon the roots of grass and corn. 



728. Section II. NOTACANTHA. The second Section of the 

 Diptera contains three families, STRATIOMID^, BERID^E, and 

 CCENOMYIDJE, which do not attract much attention, although 

 some of the species contained in them are very abundant. They 

 are mostly small but gaily-coloured insects ; and are most nume- 

 rous in moist situations, in which the larvae are generally pro- 

 duced. Some of the larvae, as that of Stratwmys Cham&leon 

 (Fig. 422), are completely aquatic ; and respire, like the larvaa 

 of the Gnats, by extending their tails to the surface, the spiracle 

 or breathing-pore being in that situation. They mostly feed 

 upon vegetable, rather than upon animal, juices. 



729. Section III. TANYSTOMA. The insects composing the 

 third section have usually a more perfect mouth, than those of the 

 other divisions ; and they are also remarkable for the structure 

 of the head of the larvae, which possess two claw-like appen- 

 dages, by which they attach themselves to the substances that 

 afford them support. Many of the perfect insects are eminently 

 carnivorous or insectivorous; as are also some of the larvae. 

 There is a genuine metamorphosis in this group ; the larva-skin 

 being cast off at the entrance of the animals into the pupa-state. 

 In this state they much resemble the perfect insect ; the limbs 

 being inclosed in distinct sheaths, and folded on the breast. 



