The Pupa. When the grub is full-fed it spins a cocoon 

 (Plate II., Fig. 7), composed of semi-transparent silk, usually 

 in some crevice or cranny or down a hollow stem. Inside the 

 cocoon it turns to a pupa. 



The Perfect Insect or Imago (Plate II., Fig. 4). The 

 illustration shows one of the brilliant green Lacewings which 

 may be found alike in town and country, and is probably 

 familiar to most. Its delicate appearance and beautiful 

 coloration will readily distinguish it from all other insects 

 likely to be met with. Those in search of it should look 

 specially in the neighbourhood of buds covered with Greenfly, 

 and it may often be seen flying rather slowly at sundown ; later 

 it sometimes comes to lights in houses. 



ARTIFICIAL ENCOURAGEMENT OF BENEFICIAL INSECTS. 



Five kinds of insects extremely beneficial to the farmer, 

 gardener and fruit-grower in fact, to all whose activities take 

 them amongst plants for their cultivation have been touched 

 upon. The five taken do not exhaust the list but are chosen as 

 being by far the most important. 



Apart from the obvious duty of avoiding their destruction 

 whenever possible, the question naturally arises as to whether 

 beneficial insects can be increased or encouraged artificially. In 

 this connection there are two distinct possibilities : (1) the 

 introduction of new kinds of parasitic insects into countries in 

 which they do not already exist ; (2) the increase by artificial 

 means of parasites already established in a country. With 

 regard to the first possibility, it has been clearly demonstrated 

 that where a foreign pest has been introduced into a country 

 without its parasites, then great good may result if such parasites 

 are brought in and released. Thus, if England is so unfortunate 

 as to be colonised by a foreign insect, one of the methods of 

 defence will be to make sure that all the invader's parasites and 

 diseases are introduced as well. An instance in which this 

 method of pest control has proved a great success is that of the 

 destructive Australian Scale Insect (Icerya purchasi, Mask.), which 

 has spread from Australia to other countries. It is difficult to 

 control by artificial means, but is kept down completely by its 

 natural enemy, a Ladybird (Vedalia cardinalis, Muls.), which is 

 now introduced to any country in which the Scale Insect obtains a 

 foothold. In the same way Ichneumons have been introduced 

 into America and other countries to combat foreign insect 

 enemies which have already established themselves. 



Under these conditions, artificial encouragement of parasites 

 is a proved success, but the case is far otherwise when attempts 

 are made to increase artificially the numbers of a parasite 

 already plentiful. It cannot be said that attempts to this end 

 have been generally successful, and it is only under special 

 circumstances that even hopeful results can be claimed. The 



