( Ixxiv ) 



the bottom of which was placed a layer of earth about two 

 inches deep, and a bank of earth three or four inches high and 

 about the same thickness was made at one end, the earth 

 being damp and tightly pressed. At the other end a small 

 shallow glass vessel was placed, nearly full of water and con- 

 taining some water weeds and a larva. The larva was fed on 

 earthworms and when full fed it easily climbed out of the 

 water and soon discovered the suitably arranged bank. The 

 larva could be hindered from commencing its work for a few 

 hours by placing a glass plate in front of the bank, and when 

 this was removed the larva at once started operations. Full- 

 fed larvae were found in July, August, and September. They 

 are very active on leaving the water, sometimes travelling ten 

 feet or more from a pond before finding a suitable site for 

 pupation. 



In making the cell the larva removes in its jaws a small 

 mass of earth from the face of the bank, turns round, and 

 then, opening its jaws, it pushes out the earth with its anterior 

 legs, depositing it to one side or behind it, thus gradually 

 making a cavity in the bank and forming a little curved wall 

 against the face of the bank. The inner surface of the wall 

 is made quite smooth by pressure of the flat head, and the 

 globular cavity which is also smoothed off is finally closed in 

 by the mass of earth removed from the interior. The larva 

 takes about six to eight hours to dig itself in out of sight, 

 keeping at work nearly continuously. 



The pupa was disclosed about a week after the larva had 

 disappeared from view. It may be easily seen on carefully 

 removing the exterior wall of the cell or on cutting the earth 

 away and opening up the cavity from the roof. It is per- 

 fectly white at first, and only the eyes show any darkening 

 for a time. It normally rests with its dorsal surface upper- 

 most, lying across the cell, supported only by the prothoracic 

 rim, which bears a number of short stiff bristles, and the two 

 fringed processes at the tail end. The whole of the body is 

 thus out of contact with the surrounding earth except the 

 two small supporting areas at the anterior and posterior 

 extremities. If disturbed, however, the pupa gives a wriggle 

 causing it to fall over on its back, but very soon another 



