1903.] H. W. Peal — Monograph of the Oriental Alenrodidse. 65 



that tho pest may increase amazingly and do extensive damage. In 

 tbis case its natural parasite being absent, the most suitable remedial 

 measure would naturally be a search for and importation of the parasite. 

 Care would have to be taken of course that no hyperparasites were im- 

 ported as well. In my opinion I think it may be taken for granted that 

 in its native habitat and under the check of its parasites, a pest cannot 

 ordinarily, without other assistance, be eradicated by means of these 

 natural parasites, as the balance has been adjusted after many genera- 

 tions of struggle between the parasite and its victim. 1 In the case how- 

 ever of an imported parasite the case is quite different ; the environ- 

 ment, climatic conditions, abundance of food and the like will be differ- 

 ent from that in its native habitat and the pest will take some time to 

 settle down in its new home. While in this as it were transitory stage 

 the parasite (imported without its own parasites) will probably have a far 

 greater power to check the pest. 



I have never observed lady birds feeding on any of these insects 

 but it is possible that they do so. 



CHAPTER IV. 



Characters and Classification. 



The Aleurodidas are a family of insects belonging to the Order 

 Hemiptera, Suborder Homoptera. 



Characteristics of the family : — 



Adult. Furnished with four wings in both sexes. Sucking and 

 digestive organs present. Eyes usually constricted or reniform, some- 

 times completely divided. An ocellus above each eye. Antennas seven 

 jointed. Tarsi dimerous and furnished with three claws. Pore wings 

 with one median and one basal vein (in the genus Aleurodicus there is 

 also a terminal vein). The wings usually white, sometimes spotted or 

 banded with red or grey. The surface of the wings mealy. 



Puparium. Scale-like. Brown, black or yellow in colour. The 

 dorsum sometimes covered with a waxy secretion. The most important 

 characteristic is the vasiform orifice described below. 



Larva 1st stage. Shape elliptical. Furnished with short stout 

 legs and antennas. The other larval stages similar to the puparium or 

 last quiescent stage. 



Egg. The eggs are bean shaped, curved and are attached to the 

 leaf by a short peduncle or stalk. 



In the adult stage these insects can be distinguished from the 



1 It cannot, we think, be said that there is ever a ' straggle ' between the 

 parasite and its host ; the lessened food supply available for the former is entirely 

 brought about by its own actions. Hon, Edit. 



