430 



THE INVERTEBRATA 



mobile; meso thorax much reduced; metamorphosis complete, larvae 

 (see p. 401) campodeiform or eruciform or, more rarely, apodous. 



In the larvae the head is well developed (Fig. 300) and the 

 mouth parts are of the biting type, resembling those of the adults. 

 The most primitive larvae are those of the campodeiform type (found 

 for instance among the Cicindelidae (tiger beetles), Carabidae and the 

 Staphylinidae). They are very active in movement and often pre- 

 daceous, with well-developed antennae and mouth parts, and chitin- 

 ized exoskeleton. In the erucijorm type (Fig. 300 B), found among 

 plant-eating forms like the lamellicorn beetles, the legs are shorter, 



Fig. 319. External anatomy of Calosoma semilaeve, with left elytron and wing 

 extended. After Essig. an. antenna; el. elytron;/), palp; sp. spiracles. 



and the animal much less active in its search for food, the body 

 bulkier and cylindrical. Finally there is the apodous type which is 

 found in the Curculionidae (the weevils), in which not only are the 

 thoracic legs lost but the antennae and mouth parts are reduced 

 (Fig. 300 C). The apodous and eruciform larvae usually live inside 

 the soft tissues of plants or beneath the soil attached to roots. 



The relation which these larval forms bear to one another is in- 

 dicated by the larval stages passed through in the life history of the 

 oil beetle, Meloe, the larvae of which are parasitic on solitary bees of 

 the genus Andrena. The first instar is known as the triungulin. This 



