INSECTS. 



107 



into a beetle in autumn. A pea inhabited by such an 

 insect can be recognized by a black translucent patch, 

 since the beetle has become a pupa immediately under 

 the seed-coat. Late the following spring the beetle 

 crawls out. As the beetles are usually still in the peas 

 at the time of sowing, the process brings them into 

 the fields. Later on, when the beetles crawl out, they 

 lay^their eggs in the ovaries of the flowers of the 

 pea-plants, which have meanwhile developed. The 

 rernedies are, consequently, — late sowing of the peas, 

 or killing the beetles in them by exposure (for two 

 minutes) to a temperature of 122° Fahr., or for ten 

 minutes to sulphur dioxide fumes in a closed space. 

 The remaining three species of Bruchus have the same 

 habits as the bean beetle, but the insect often creeps 

 out much earlier, so that the seeds do not require 

 treatment. 



The Pea Weevil {Sitones lineatus). Longish, with 

 grey scales on a black background. Neck-shield 



Fig. is, — Attacks of Pea Weevil : a, b, on pea leaves ; c, on a bean leaflet. 



with three longitudinal streaks, wing-covers with 

 dotted lines. These weevils appear at the first 

 beginning of spring on peas, field and garden beans, 

 clover, and vetches. They gnaw the leaf-margins of 



