238 COLEOPTERA 



CHAP. 



and Acari thar are so injurious to cultivated plants. They 

 also eat various other soft-bodied Insects that attack plants. As 

 thev are excessivelv voracious, and are themselves sin<nilarlv 



* t, t 



free from enemies and multiply with great rapidity, all these 

 features of their economy render them of inestimable value to the 

 agriculturist and horticulturist. The species of the sub-faniily 

 Epilachnides feed on plants, and one or two are occasionally in- 

 jurious. The body-fluid of Coccinellidae has an unpleasant odour 

 and taste. Many lady-birds have the power of exuding, when 

 disturbed, small quantities of a yellow fluid. Lutz has shown that 

 this is not a special secretion, but an exudation of the fluid of 

 the body that takes place through a small orifice at the tip of 

 the tibia, from pressure caused by contraction of the body and limb. 1 

 The larvae are much more active than beetle-larvae usually 

 are, and many of them are very conspicuous when running about 

 on plants to hunt their prey. They usually cast their skins 

 three times, and sometimes concomitantlv change a good deal in 







colour and form : the larval life does not usuallv exceed four or 







five weeks : at the end of which time the larva suspends itself 

 by the posterior extremitv. which is slued bv a secretion to some 



* -L . * v 



object ; the larval skin is pushed back to the anal extremity, 

 disclosing the pupa : this differs in several respects from the 

 usual pupa of beetles : it is harder, and is coloured, frequently 

 conspicuously spotted, and dehisces to allow the escape of the 

 beetle, so that the metamorphosis is altogether more like that of 

 Lepidoptera than that of Coleoptera. There is much variety in 

 the larvae ; some of them bear large, complexly-spined, projections : 

 those of the group Scymnites have small depressions on the 

 surface, from which it has been ascertained that waxy secre- 

 tions exude : but in Scymnus minimus no such excretions are 

 formed. Certain species, when pupating, do not shuffle the skin to 

 the extremitv of the bodv, but retain it as a covering for the 



e. t, ' O 



pupa. The larvae that feed on plants are much less active than 

 the predaceous forms. "\Ve are well supplied with Coccinellidae 

 in Britain, forty species being known here. 



The systematic position of Coccinellidae amongst the Coleoptera 

 has been for long a moot point. Formerly they were associated 

 with various other beetles having three-jointed, or apparently 

 three-jointed, feet, as a series with the name Trimera, or 



1 Z<jol. virt:. sviii. 1895. p. 244. 



