214 



SUBKINGDOM AETICULATA. 



tube on the last segment of the body, till they change into 

 the pupa state, when respiration is transferred to two tubes 

 in the thorax. Assuming the imago state, they burst through 

 their envelopes, and rise from the water perfect insects. 

 There are three or four generations in a season. The female 

 alone has a piercing proboscis, which for fineness is to the 

 point of a needle as that is to a sword.* 



Fig. see. 



Ceddomyla destnuitor, Hessian Fly ; (!. triCiei, Wheat Midge j 



LarDce of latter feeding in wheat-fkmtrs, magnified. 



Cecidomyidse (high-leaping family). — The Hessian and 

 the Wheat Ply are injurious to v/heat, some species by attack- 

 ing the flower and some the stalk. 



Miascidse. — Plies can walk upon 

 ^^- *'''• smooth surfaces overhead, because the 



broad disc of the foot secretes a vis- 

 cid fluid, by which they adhere. In 

 the imago state there is no growth, so 

 that smaller and larger specimens of 

 flies are different species, f 



Foot of House-fly. 



* Its minute wound should quickly heal ; hut 

 whether the irritation results from the injection of 

 a poisonous liquid, or from the barhed prohoscis, as 

 well as how its hum is produced, are unsettled ques- 

 tions. 



+ The common House-fly is an importation from 

 Europe, and according to Packard {American Nat- 

 uralist, Aug., 1876) its life may be summed up as 

 follows ; " It lives one day in the egg state, hatched 

 m the ordure of stables ; from five days to a week as 

 a maggot ; fi-om five to seven days in the pupa state, 

 —in all from ten to fourteen days in the month ol 



