20 INSECTS NOXIOUS TO AGRICULTURE. 



duce young is perhaps one of the most mysterious things in 

 Nature. The male of Mytilaspis pomorum has never been found 

 in New Zealand or Europe, and doubtfully in America. 

 Lecanium hesperidum has been known and studied for nearly two 

 hundred years without any male, pupa or adult, being discovered. 

 Yet both of these species go on increasing regularly and in great 

 numbers, and show no signs of extinction. 



In spite of this absence of males in some cases, and of the 

 comparatively small numbers of eggs, Coccids would naturally in- 

 crease at an exceedingly rapid rate if left undisturbed, on account 

 of the great proportion of females. They are, moreover, pro- 

 tected, to a great extent First, by the fact that birds do not, as 

 a rule, care to eat them. The " blight-bird " or " white-eye," 

 Zosterops lateralis, has been noticed in this country pecking about 

 in holly-hedges infested by Lecanium hesperidum ; but it is not 

 absolutely certain whether it was eating the Coccids or the other 

 more easily picked-off insects on the plant, such as Psocus, which 

 is very commonly observed among Coccids. And other birds 

 seem not to devour them at all. Secondly, the usual position of 

 these insects, on the under side of the leaves, or in the crevices 

 of bark, is a great shelter and protection for them against birds 

 or ordinary accidents. Again, they are in many cases effectu- 

 ally covered by the waxy or fibrous shields, or by the masses of 

 cotton with which they surround themselves. In countries like 

 the South of France, California, or the greater part of New Zea- 

 land, the winters do not appear to be sufficiently severe to injure 

 Coccids, and many of them breed as much in winter as they do 

 in summer. It would therefore seem that everything combines 

 to assist these insects in their career, and in their propagation. 

 Nature, however, has provided a check which is to some extent 

 effective, at least against several species, although, unhappily, 

 against some of the most noxious such as Mytilaspis pomorum, 

 the Dactylopii (mealy bugs), leery a purchasi, &c. it is not 

 energetic in this country; and this remedy is the attacks of other 

 minute animals, whether by direct devouring of the Coccids or 

 by parasitism. 



Direct attacks from animal enemies are not frequent. 

 Whether from some inherent distastefulness, or from the diffi- 

 culty of getting at them, Coccids are scarcely subject to being 

 directly devoured. There are a few exceptions. Under the 

 puparia of Mytilaspis pomorum a minute white Acarus (mite) 



