THE FEMALE. 15 



beautiful symmetrical design. I have elsewhere noted 

 these insects carry their eggs and young between the 

 anal plates, Avhich act as a sort of marsupium or cradle. 

 Of the much- dreaded fluted scales, Iceri/a ser/yp- 

 tiacum, Douglas, was introduced (? from India) to 

 a garden in the London district; but, thanks to the 

 discoverer, it was speedily eradicated, and, I believe, 

 has not since been met with. Of course it is always 

 difficult to say how a newly introduced pest may act ; 

 but, given favourable conditions such as it would meet 

 with in our hothouses, I see no valid reason why the 

 insect should not thrive and be equally destructive 

 among our exotic plants as other aliens have been. 



THE RESPIRATORY SYSTEM. 



A young female Lecaniam affords an excellent ex- 

 ample for the study of the respiratory system. The 

 branched tracheas can be plainly seen to penetrate the 

 body, and to be connected with four comparatively 

 large openings or spiracles placed equidistantly on the 

 ventral surface of the body, well within the margin 

 and near the line of insertion of the legs. Extending 

 from each of the spiracles to the outer margin of the 

 insect is a deep semicircular channel, which is almost 

 invariably filled with fine white wax in a powdery 

 form, which probably acts as a filter, and prevents the 

 ingress of excessive moisture. If a gravid female be 

 removed from its food-plant it will almost invariably 

 leave behind it a white scar or mark, indicating its 

 outline and the exact position of the four channels 

 leading to the spiracles. 



In the remarkable exotic genera Stigmacoccus, Hem- 

 pel, and Perissopneumon, Newstead, the two pairs of 

 ventral spiracles are supplemented by a series of 

 others, arranged along the margin on the dorsal sur- 

 face. In the former there are eight, and in the latter 

 seven pairs, but this peculiarity does not exist in any 

 other Coccid, 



