October, '16] 



ESSIG: CHRYSANTHEMUM GALL-MIDGE 



465 



chrysanthemum gall-fly and is by far the most efficient and satisfac- 

 tory way of handling the situation. The j^oung clean selected plants 

 are propagated from the beginning in these insect-proof cloth houses 

 and every precaution is taken to keep them clean and tight. 



In greenhouses the difficulties are very great. Eliminating all 

 infested plants and using only clean cuttings have given fairly good 

 results, but means a continual fight from the very beginning to pre- 



Fig. 33. Some detail anatomical characters of Ainblymerus sp., a parasite of the 

 chrysanthemum gall-fly. A, win^s; B, antenna; C, middle tarsus; D, tibial spur 

 on front leg; E, tibial spur on hind leg; F, mandible. Greatly enlarged. (Original). 



vent reinfestation. Some florists take only underground cuttings from 

 infested plants and get satisfactory results when all of the old plants 

 are destroyed before the flies begin to emerge in the spring. 



In lath houses there is continual danger of infestation which can 

 hardly be avoided. One practice which works very well where the 

 old plants are allowed to come up again during the winter and spring 

 is to cut back the young shoots in November or December and again in 

 February or March and burn the trimmings. In this way most of the 



