112 ENTOMOLOGICAL SOCIETY 



life is generally prolonged, while that of the adult is limited to a 

 few weeks or, at farthest, a few months. This is essentially 

 true of all those species which, in the larva state, bore within the 

 trunks or branches of trees, as in the Cerambycidae and allied 

 families, and of those which feed upon the roots of plants under 

 ground, as in the Scarabaeidae and various genera of the Chrys- 

 omelidae, and of the Rhynchophora. It is more or less true of 

 those species which feed upon dung and decaying vegetation, and 

 of the great bulk of the Carabidous section of the predaceous 

 forms. Yet, even in these cases, the term of larval life, under 

 normal conditions, rarely exceeds three years, and more often not 

 quite one. With the great bulk of the leaf-feeding species, 

 however, we have, on the contrary, hibernation for the most part 

 in the adult state and the larval period correspondingly short 

 ened ; whereas in the parasitic forms, irrespective of the families 

 to which they belong, we have a mode of life dependent upon 

 that of the host, and the adult is generally very short-lived as 

 compared with the larva. This last manifests, indeed, a varying 

 power to live in some instances in a quite remarkable manner, 

 even without food. The habits of the triungulin in the Meloi'dae, 

 and the very ephemeral existence of the male of the Stylopidae 

 as compared with that of the female, are illustrations in point. 

 But no rule can be formulated as to the Order, because there 

 sometimes occur in the same genus species which are two- or 

 many-brooded, and species which are single-brooded annually, 

 as also species which hibernate either in the larva or in the imago 

 state. 



In this Order, again, great adaptability to circumstances is 

 indicated by the few observations and experiments that have 

 been made. Thus, as I have shown in the Tenebrionidae and 

 Dermestidae (Am. Nat., May, 1883, Vol. xvii, pp. 547-48), 

 the larvae will, where food is withheld, linger for a term of 

 years and develop the power of moulting more frequently than 

 they would normally have done if they had had an abundant 

 food supply. There are many recorded cases of such prolonga 

 tion of life in the Ptinidae and the Cerambycidae, when confined 

 in dry wood made up into furniture, and almost every ento 

 mologist has had experience of such cases. O. Nickerl has 

 recorded in his Beitrage zur Kenntniss vom Lebensalter der 

 Insekten (Stett. Ent. Zeit. 50, 1889, pp. 155-163) that a female 

 specimen of Carabus auratus found July 28, 1884, was fed 

 and kept in confinement, and lived until June 21, 1889, or 

 nearly five years, having hibernated five times. He believed 

 that the specimen was not impregnated, and that the nor 

 mal larval life is two years. A female specimen of Calosoma 



