276 



Marvels of Insect Life. 



it appears to be mainly occupied in visiting flowers to feed upon pollen. 

 Two species have certainly got the black and yellow banding of the wasps. 

 They are probably only forms or varieties of one species which we may term the 

 girdled drone-fly.^ Although it has the black and yellow livery, it cannot be said 

 to have any strong form-resemblance to a wasp ; and we do not think that its 

 coloration is at all for the purpose of imposing upon the wasp, but rather for its 

 own protection from fly-catching birds who would understand the colours to indicate 



that it is not edible. 



It should be stated that the term drone- 

 fly is used sometimes for the fly that develops 

 from the rat-tailed maggot,- and is more 

 generally known as the hover-fly. 



Scale-Insects. 



Although the scale-Insects '^ are all plant 

 parasites that spend their existence in sucking 

 the juices of plants, and many exist in millions 

 on a single tree, they are mostly unknown 

 except to practical gardeners and naturalists. 

 Some of them are absolute pests on plants 

 under glass, and most of these have at some 

 time or other been introduced from abroad 

 with the plants they chiefly aftect. Those that 

 are real natives of our islands are mostly found 

 upon trees and shrubs in the open air. They 

 are somewhat akin to the green-fly, but those 

 individuals that have wings only possess one 

 pair. The winged Insects are always males, 

 but not all males have wings. The males are 

 much less numerous than the females, and in 

 many species the males have not yet been 

 discovered. One peculiarity of a male is that 

 it never has a mouth. It can take no food, 

 and the sole reason for its existence is the 

 fertilization of the female. Even this does 

 not appear to be necessary to the continuance 

 of the species, for many generations of fertile 

 females may be produced in succession without 

 the intervention of a male. But these genera- 

 tions difler from those of green-fly in that they 

 are not produced rapidly : there is only one 

 brood in a year, but an enormous number of 

 eggs are laid by one female. Exotic species 

 found in our glasshouses know little of our 

 seasons ; and these produce more than one 



- liiistalis tenax. •' Coccida; 



Photos by] [W. West. 



In the first of these two photographs the adult female is 

 shown from the under and upper sides respectively, with 

 the long cloak of wax in two stages of development. 

 The second photograph shows the same Insect in a 

 younger condi tion before the wax plates have been formed. 

 The first photograph is twelve times larger than the actual 

 size of the Insects, and the second is twenty-eight times. 



^ Volucella zonaria and V. inanis. 



