138 OUR INSECT FRIENDS AND FOES 



produce silkworms that, on the day before they 

 cease to feed, devour as much in weight as the 

 food of four horses ! 



Next in order to the silkworm, which is far 

 and away the most important of commercial 

 insects, comes the cochineal insect (Coccus cacti) 

 a member of a strange group of insects belong- 

 ing to the Order Hemiptera. Several species of 

 the Coccidce family are of considerable com- 

 mercial value, while others do a great deal of 

 harm to plant life. 



The life history of the Coccidae is very 

 peculiar, and the male and female are so unlike 

 each other in appearance that they might easily 

 be mistaken for different species of insects. 



In the larval state the young Coccus look 

 very much like tiny tortoises, and run actively 

 about the plants on which they feed. When full 

 grown the female, without undergoing any 

 change of form, fixes itself to the plant by the 

 beak, or rostrum ; and in this position it remains 

 throughout the whole of its adult life, which 

 lasts for several months, sucking up the juices of 

 the plant, and becoming more and more swollen 

 and shapeless, until it looks just like a little lump, 

 or excrescence, on the tree, and is about the size 

 of a plump currant. The male (which is much 

 smaller than the female) in the perfect state 

 possesses a pair of delicate, gauzy wings (the 

 hind pair being represented by halteres), feathery, 

 beaded antennae, and two fine caudal bristles 

 which are twice the entire length of its body. 

 Curiously enough, while the female spends the 

 whole of her life is absorbing nourishment, the 



