April, '05] ENTOMOLOGICAL NEWS. 1 17 



Some Notes on the Habits and Life History of 



Bembecia marginata Harris in 



Western Washington. 



BY W. H. LAWRENCE, Agricultural College, Washington. 



The so-called Raspberry Root Borer or Blackberry Crown 

 Borer, Bembecia marginata Harris, has found its way into some 

 of the berry fields in Western Washington. The habits and 

 life history vary somewhat from those described in other sec- 

 tions. Scattering observations made during 1901 to 1904, 

 show that it takes a period of two years for the transformation 

 of the insect. It has been particularly easy to trace the trans- 

 formations, as but a single brood occurs in this section. 



During 1903 adults reared from pupae and adults captured in 

 the field were confined in cages and in a large .glass jar. In 

 the latter, raspberry slips were placed in a dish of water. 

 Numerous eggs were deposited in these cages. The females 

 endeavored to place each egg beneath the object upon which 

 they were resting ; many were placed on the under surface of 

 the leaves in the jar. 



In the field the moths alight on the upper surface of black- 

 berry or raspberry leaves. When ready to deposit their eggs 

 they begin to flutter their wings, rise on " tip-toe," move side- 

 wise, bend the abdomen around the edge of the leaf and 

 deposit a single egg beneath. During the season not a single 

 egg was found on the canes at any point high or low all were 

 on the lower surfaces of the leaves. 



The eggs are oval, of a deep reddish brown color, and about 

 j'g- of an inch long.' A single moth lays about 140 ; those con- 

 fined in cages laid from 135 to 150. A large number of eggs 

 were kept on dry earth in the bottom of a breeding cage ; 

 others were kept on the wooden floor of a cage. Leaves col- 

 lected in the field, on which eggs had been deposited, were 

 also placed in these cages. Canes, on the leaves of which eggs 

 had been deposited, were placed in water in jars, and kept 

 alive as long as possible. The location of each of a large 

 number of eggs on leaves in the field was marked. Not an egg 

 on wood, dry earth, or dry leaves in the field, hatched. A 



