MEALY BUG WITH LONG THREADS 



253 



ing on her head. When the young hatch they spread in all direc- 

 tions over the plant, generally settling along the midrib or on the 

 under side of the leaves, or in the forks of the young twigs. They 

 form closely packed colonies at first, and at this stage there is 

 only a slight covering of the powdery secretion referred to above. 



Injury. The mealy bug is a very troublesome pest in green- 

 houses, for it attacks almost all plants. However, when the 

 greenhouses are fumigated at regular intervals, these insects are 

 rarely troublesome. 



Control. Nicotine sulfate or whale-oil soap may be used. If 

 only a small number of plants are to be treated, the pyrethrum 

 decoction is to be recommended. 



FIG. 255. The mealy bug with long 

 threads, male. (After Comstock.) 



FIG. 256. The mealy bug with long 

 threads, female. (After Comstock.) 



The Mealy Bug with Long Threads (Dactylopius longifilis 

 Comst.). This bisect resembles the previous pest very closely 

 except in technical details. The lateral filaments are seventeen 

 in number and are quite long, and the last on each side is equal 

 to or longer than the body. These filaments give the bisect its 

 name. The female surrounds herself, when mature, with a cottony 

 substance, amid which the young cluster for a time. The larval 

 male forms a small cotton cocoon in which it pupates and from 

 which the winged adult emerges. The transparent wings expand 

 only one-tenth of an inch. 



Control. The same remedies and methods of prevention are 

 applicable to this bisect as to the preceding. Lady-bird beetles 



