244 The Pea TJirips (Kakothrips robustus) 



The burning of the pea sticks during the winter, frequently re- 

 commended, is of no use. Many thrips may be beaten from the sticks, 

 but not this species (chiefly Limothrips cerealium and species of the 

 sub-family Tubulifera). 



Notes on Methods of Collecting and Breeding. 



Thrips for identification purposes are of no use when dry. They 

 should be collected into 70 % alcohol, or a mixture of 70 % alcohol and 

 glacial acetic acid in equal parts. In the latter case they must be 

 transferred after a few hours into 70 % alcohol. The latter method is 

 better for larvae as they are less distended than in the alcohol alone. 

 For critical examination they must be cleared and mounted in balsam 

 as a microscope preparation. I find Griibler's 'Turpineol' the most 

 satisfactory clearing agent as it leaves the insects sufficiently pliable 

 to allow of the moving of the wings and legs into suitable positions. 



Living specimens of pea thrips have been obtained from all over 

 the country in parchment bags closed with slide-on paper fasteners. 

 These bags are sent out in suitable boxes with instructions to fill with 

 flowers or pods placed in the bag straight after picking. In this way 

 material was obtained from friends and others who knew nothing of 

 entomology, many not even knowing by sight the thrips "in question. 

 Many other thrips and insects were found in the bags in which the plants 

 would keep fresh for four or five days, and the method appears to be 

 worthy of wider application. Most of the bags I used were supplied 

 by Messrs Miller and Sons, Kenfield Street, Glasgow, but the bags 

 sold for 'paper bag cookery' also answer quite well. They should, 

 however, be as transparent as possible as some idea of the contents can 

 then be got by holding up to the light before opening. 



Eggs were obtained, and larvae bred in small glass tubes plugged 

 with cotton wool. Frequent changing was necessary or the moisture 

 which condensed on the sides of the tubes was a great danger, and the 

 sun should on no account be allowed to shine directly on to the tubes. 

 Larvae were hibernated in beakers filled with soil and in flower pots 

 sunk in the ground. They were also obtained in soil during the winter 

 with Berlese's 'Insect Funnel' which, by means of warmth, extracts 

 all the small insects from the soil which is placed in a sieve at the top^ 



^ I have given a short account of this in the Entuniokxjist, XLVi, 1!>13. ]). 273. 



