294 COLEOPTERA CHAP. 



of parasites as other Insects do. We have not the least reason 

 for supposing that this mode of life for a larva is, so far as 

 utility is concerned, better than a more simple and usual one. 

 Indeed, extraordinary as this may appear, it is well known that 

 other species of the same genus adopt a simple mode of life, 

 laying their eggs in young fruits or buds. We think it possible, 

 however, that a knowledge of the mode of feeding of this larva 

 may show that a more perfect nutrition is obtained from a well- 

 constructed cylinder, and if so this would to a slight extent 

 satisfy our longing for explanation, though throwing no light 

 whatever on the physiology or psychology of the artificer, and 

 leaving us hopelessly perplexed as to why a beetle in ages long 

 gone by should or could adopt a mode of life that by long pro- 

 cesses of evolution should, after enormous difficulties have been 

 overcome, attain the perfection we admire. 1 



Fam. 82. Scolytidae. Eostrum extremely short, broad ; tibiae 

 frequently denticulate externally; antennae short, with a broad 

 club. This family is not at all sharply distinguished from certain 

 groups of Curculionidae (from Cossonides e.g.}, but as the species 

 have somewhat different habits, and in the majority of cases 

 can be readily distinguished, it is an advantage to separate 

 the two families. About 1400 species are at present known. 

 Most of them are wood- and bark -feeders ; some bore into hard 

 wood ; a few mine in twigs or small branches of trees, but the 

 majority live in the inner layers of the bark ; and this also 

 serves as the nidus of the larvae. A small number of species 

 have been found to inhabit the stems of herbaceous plants, or to 

 Live in dry fruits. Owing to their retiring habits they are rarely 

 seen except by those who seek them in their abodes, when they 

 may often be found in great profusion. The mother-beetle bores 

 into the suitable layer of the bark, forming a sort of tunnel and 

 depositing eggs therein. The young larvae start each one a 

 tunnel of its own, diverging from the parent tunnel ; hence each 

 batch of larvae produces a system of tunnels, starting from the 

 parents' burrow, and in many species these burrows are charac- 



1 For a more extensive account of Rhynchites betulae and others refer to 

 Wasmann. Der Trichterwickler, Minister, 1884, and Debey, eitraye zur Lcbens- 

 und Entwickelungs-geschichte . . . der Attelabiden, Bonn, 1846. The first in- 

 cludes an extensive philosophical discussion ; the second is a valuable collection 

 of observations. 



