XF.CKOPTEKA. 



221 



more than half as long as the rest of the body. This species is 

 common throughout the greater part of the United Si The 



^^^t arc called " Dobsons" by anglers, and are used by them for 

 W^^ ially for bass. Fig. 191 represents a fully grown Dob- 



natural size. There is on each abdominal segment a pair of 

 ioi {tapering appendages; those of the ninth 

 -bi.ominal segment are carried back so as to 

 pp ject from the sides of a pair of anal pro- 

 These pro-legs project caudad, and are 

 nished each with a pair of claws. At the 

 of each lateral appendage on the first 

 ven abdominal segments there is a tuft of 

 1 I'r-like tracheal gills. The larva also has 



a remarkable instance of an ii: 

 provided with both organs for aquatic and 

 aerial respiration. The spiracles are probably 

 not used till the insect is fully grown and 

 leaves the water to undergo its transforma- 

 tions. These larva, 4 live under stones in the 

 bed of streams. They are most abundant in 

 the swifter parts of the stream. They are 

 carnivorous, feeding upon the lame of Stone- 

 5, and other insects. When 

 about two years and eleven months old, the 

 lar. .< water and makes a cell under 



a stone or other object on or near the 

 bank of the stream. This occurs at Ithaca during tlx part 



of Mayor early in June. By the middle of June the majority of 



irv;L> have tran.sfnrmed to pupae. These are of a yellc 

 white color. Tlu-y are furnished with rudimentary uings and 

 and quite long antenna.-. During the last half of June the pupae 

 change to the adult state. The egg- >n laid. I 



to stones or to other objects overhanging th< 

 They are laid in blotch-like massi-^. which are chalky \\hiti 

 and m< 'mm 12 to 20 mm. in diameter. A 



<1 to th; *. Wli 



at once find their way i 

 till fully grown. 



',/. This jr.-- 1 in this country only on the 



the of: 

 family by having the prothorax cylindrical, and in : 



FIG. 



fa. larva. 



