104 



Lessons in Zoology. 



layer. Some of the harveBt-flies have two broad plates 

 on the under side of the abdomen. 



These plates are fonnd on the male, and cover the kettledrnms, 

 by which he makes the shrill sonnd we know so well in doK-dajB. 



The month-parts having been desoribed in the last lesson, are 

 omitted here, bnt wonld of conrse be reviewed in the schoolroom. 



The papa has very large fore legs, like great claws. 

 It has a sucking- tube like its parent. All the rings of 

 the thorax show plainly. The first and second rings are 

 very large ; the third ring is small. The horny outer 

 layer of the antennae and the eyes is cast off with the rest 

 of the skeleton. 



Fig. 2. 



Fig. 3. 



With the strong, horny piercer at the end of the abdomen the 

 female makes hollows in twigs in which to lay her eggs. The 

 larva (Fig. 2) is hatched on the tree, bnt lets itself fall to tiie 

 ground, being so light that it descends very slowly and is not injured 

 by the fall. It then borrows in the earth, where it ancks the sap 

 from roots. One species of harvest-fly passes seventeen years in 

 the earth as larva and papa ; others common in New England re- 

 quire only one or two years for their transformations. The pnpa 

 at last digs its way ont of the earth with its big fore claws, climbs 

 some tree, its skin splits on the back, and the harvest-fly comes ont. 



Fig. 3 shows the inseet making its way ont of the pnpa skin. 



The water-boatman, mentioned in the last lesson, is a different 

 type, and shonld be studied from living insects kept in jars in the 



