THE CANADIAN ENTOMOLOGIST. 113 



seeing in it once more beautiful illustration of how all things living in the 

 world, whether ffora ox fauna, are adapted to their environment. 



As I have begun with one of the weevils which come at the end of 

 the Coleoptera in classification, I will pass to a family not far removed 

 from the weevils, the Blister Beetles ( Meloidce), many of which in the 

 mature state occur abundantly on foliage and are very destructive. Four 

 species of the genus Epicauta are known in Ontario ; some of them 

 occasionally attack the leaves of the potato, but more usually they feed 

 harmlessly on flowers like golden-rod and helianthus or the low herbage 

 by river bank?. I have not seen any of this genus, and think it uncommon 

 east of Toronto, or at least in the neighbourhood of Port Hope. One 

 species of an allied genus ( Macrobasis u?iico/or), which also attacks the 

 potato, I have found in great abundance about Port Sydney in low grounds, 

 feeding and b*"eeding on the foliage of meadow-rue. The family consists of 

 two tribes, Cantharida and Meloidce. The former all have power of flight, 

 and are frequently found about foliage or flowers ; in the latter the wings 

 are abortive or entirely absent, and the beetle's most daring excursions into 

 the realm of air consists in crawling up a grass-blade or the stem of some 

 herbaceous plant. One or two species of Meloe or Oil Beetle are 

 frequently found early in the spring and late in the summer, but the insect 

 does not appear to eat foliage. Both tribes of this family are famous for 

 their possession of a principle known as cantharidine, whence they are 

 called Blister beetles, some of the species being of great medicinal value. 



A more remarkable feature about them, which they share with some 

 of their neighbours, the Mordeliidce. is the phenomenon of hyper-meta- 

 morphosis. They are all parasitic in the larval stage, their hosts being 

 usually bees, occasionally wasps and (in the case of Epicauta) locusts. 

 The normal form of the larva is preceded by a very active louse-like 

 insect known as a triungulin (each leg terminating in a triple set of hooks). 

 The larva that succeeds the triungulin is inactive and almost legless ; 

 moreover, in some cases the true pupa is preceded by a sort of prelimi- 

 nary pupal form, from which emerges a larva of habit almost as active as 

 the original triungulin, though it does not feed. 



The triungulin is a monomaniac, I mean a creature of but one idea, 

 one single goal of ambition, and its six active legs-enable it to get there. 

 The loadstone that draws the triungulin like a steel-filing to a magnet is 

 the egg of its host. In the case of Epicauta vittata, this is the egg cluster 



