COCCIDyE. 



315 



that the Board of Agriculture invited Mr IS'ewstead to give evidence 

 before a special committee nreeting at the House of Commons. As 

 the result of previous studies, he was able to dispel all fears, and 

 subsequent experience has amply justified his opinions. 



As showing the wide geographical range of certain scale-insects and 

 their adaptability to varied food-plants, one species, namely, the com- 

 mon mussel- scale (Mytilasjjis pomorum), may be cited. Newstead 

 says : " It occurs as a pest in almost every part of the world where 

 the apple is cultivated — in Europe, JSTorth and South, the United 

 States, ISTew Zealand, Australia, Xorth Africa, and probably many 

 other places." 



The Coccidfe or scale-insects belong to the order Hemiptera, which is 

 subdivided into two principal divisions — viz., Hemiptera-Heteroptera, 

 which includes the bugs ; and the Hemiptera-Homoptera, which in- 

 cludes Aphididpe, Cicadae, Psyllidae, and Coccidae or scale-insects. The 

 last are broadly distinguished from other families by the ^raJe or cover- 

 imj which they spin to protect their bodies. 

 Hence the Germans call them by the express- 

 ive term Srhildlimse (shield-lice). 



Having often found that intelligent prac- 

 tical men designate scale-insects as a " very 

 low form of life," it may be well to show 

 their close relationship with other families 

 which are grouped together in the same sub- 

 order. As in point of structure and life- 

 history they are very closely associated with 

 other families of the sub-order, it may be 

 well, even at the risk of repetition, to present 

 the more salient features of each family as 

 an educational advantage to the clearer dis- 

 crimination of the relationship which exists 

 between them. All the insects of the natural 

 order Hemiptera are characterised by the 

 possession of suctorial mouths, and therefore belonf 

 division of Insecta known as Haustellata. 



The Aphididae or plant-lice are soft-bodied insects, usually green, 

 with long, rather slender legs, and not formed for leaping. They 

 occur in two forms — winged and wingless. The beak (proboscis), or 

 feeding-organ, is often very long, and the far.ois tiro-jointed. One 



Fig. 292.— Cera t 

 {fringed f/'. 

 Known to li 

 as the "blacl 



to that great 



