244 ROMANCE OF THE INSECT WORLD CHAP. 



that many possess some unpleasant quality, or 

 qualities, rendering them if caught unfit for food, or 

 even disgusting or dangerous. A widely-extensive 

 group is repugnant, and is constantly refused, owing 

 to their possession of a more or less powerful and 

 revolting taste or smell. Almost every order furnishes 

 instances of defensive scents, but few yield individuals 

 more notoriously bad in this respect than the 

 Coleoptera, Orthoptera, and Hymenoptera. Among 

 Lepidoptera, numbers of the larvae prove distasteful. 

 The chrysalis of the Magpie Moth (Abraxas 

 grossulariatd], and many butterflies and moths are 

 similarly defended. In some cases an offensive odour 

 is emitted at pleasure from particular organs. The 

 peculiar faculty of the so-called Bombardier Beetles, 

 consisting in the discharge of a volatile liquid like a 

 puff of smoke, accompanied by a distinct crepitating 

 explosion and attended by a disagreeable scent, is 

 well known. An enemy in pursuit is dismayed, and 

 arrested on its progress, enabling the beetle to gain 

 time, and probably to effect its escape. Emission of 

 strongly smelling fluids on the approach of an enemy 

 is by no means unusual. The larvae of certain 

 Sawflies (Hymenoptera} have a number of odoriferous 

 glands along the middle of the ventral surface, more- 

 over these insects are gregarious, collecting, often 

 a hundred and more, on the branches of trees which 

 they completely denude. In the event of one of 

 the larvae being touched or disturbed, it instantly 

 gives forth a drop of a clear resinous liquid from its 

 glands, and, what is still more remarkable, all its 

 neighbours, as though moved by an impulse in com- 



