BENEFICIAL INSECTS 225 



ovary, which grows to occupy the greater part of their 

 bodies, becomes filled with a light red fluid, within which 

 the eggs are formed. This red fluid forms the basis of 

 the lac dye. Each female produces as many as a thousand 

 eggs, on an average, and as they mature the mother dies ; 

 in fact, by this time she consists of little more than a skin 

 which ruptures and allows the larvae to escape. There are 

 two generations in the year, and they differ markedly in 

 that the adult males of the later generation are winged 

 (fig. 58, A), probably with the object of ensuring the fertilisa- 

 tion of the females on trees where males are scarce. The 

 time to collect the lac is obviously when the larvae have 

 left the mother scales, for then the incrustation contains 

 no insects and a minimum of the red coloration, which is 

 somewhat difficult to remove during manufacture, and 

 depreciates the value of the commercial lac. 



Cochineal 



The cochineal insect, Dactylopius coccus, is another 

 member of the family Coccidce deserving a place among 

 the useful insects ; without exaggeration, it may justly be 

 called the most celebrated of all the scale insects. Cochineal, 

 in the larval and female adult forms, is essentially parasitic 

 upon the prickly pear, Opuntia coccinellifera, though it 

 lives equally well on some other allied species. The adult 

 male is very minute, only a millimetre in length, and of a 

 carmine colour, which is intensified on its head and thorax. 

 The wings, which are longer than the body, have only a 

 single bifurcated yellowish-brown vein, and the head is 

 provided with four compound and two simple eyes, whilst 

 from the last segment of the abdomen two long bristles 

 arise. The female is about six times larger than the male, 

 measuring from six to seven millimetres in length; deep 

 red brown in colour and segmented, though the segments 

 are hidden by a white, waxy secretion. 



The life-history of this insect is so similar to that of our 



15 



