36 



INTRODUCTION. 



the Cretaceous period) the Scydmjenidje, Leptinid^e, Clam- 



BIDJE, APH^NOCEPHALID-E *, CORYLOPHIEvE, TrICHOPTERYGID^I, 



8PHiERiiDjE, Hydroscaphidje, and Scaphidiid^; ; the Platy- 

 psylliDjE also probably belong to this period. Somewhat later 

 than the Silphidje, but still in the Triassic period, come the 

 Palpicornia and Malacodermata, and a little later (but doubt- 

 fully) the Olavicornia (in Ganglbauer's sense, excluding the 

 Staphylinoidea). In the Triassic period appear the ancestors 

 of the Adephaga, Brachymera, Serricornia, JSternoxia (including 

 BuprestievE and Elaterid^), and Teredilia. Later still, in the 

 Middle Jurassic and Lower Oolite (" Dogger "), come the Hetero- 

 mera, and in the Upper Jurassic and Upper Oolite (" Malm ") the 

 Phytophaga, from which, in the Cretaceous period, the Bhyncho- 

 phora take their origin. Last of all appear the Lamellicornia. 



No Coleoptera occur in the Palaeozoic period. One hundred 

 and thirty-eight distinct types are found in the Mesozoic period, 

 and about two thousand in the Cainozoic period. The proportion 

 of beetles known in Tertiary and modern times is about 1 to 80 ; 

 the proportion for the Lamellicorns, however, is only 1 to 180, 

 which appears further to suggest their recent origin. 



Referring to the Triassic period (I. c. ii, p. 379) Handlirsch says 

 that the Coleoptera are practically impossible to define, and belong- 

 to very slightly specialised forms, out of which may be made a 

 Carabid, Dy tiscid, Tenebrionid, Chrysomelid, or Bhynehitid ; this 

 is shown by the names given to them — Pseudocurcidionites, Pseudo- 

 buprestides, Pseudocarabites, etc. This is, of course, as Handlirsch 

 incidentally points out (I. c. pp. 398-399) partly due to the fact 

 that we have only elytra to deal with, and that it is impossible 

 from these alone to recognize the families with any accuracy. 



With regard to the origin of the Coleoptera we cannot agree 

 with Handlirsch's theory that they are derived from primitive 

 forms of Blatta or from a branch of the Protoblattoidea. His 

 only arguments in favour of this appear to rest upon outward 

 appearance (the resemblance of the Blattid^e to certain Cara- 

 bidje, Silphid^e, Lampyrides, etc.), the i^ta-like form of certain 

 iSilphid larvae, the large approximate coxae, and the " egg-laying " 

 of Hydropliilus. The extreme difference of the metamorphoses 

 seems to outweigh all these, even though we allow that in a few 

 instances beetles are viviparous. 



Handlirsch seems to have more reason in rejecting Lameere's 

 theory that the Coleoptera are derived from wood-boring Neuro- 

 ptera which have had their upper wings modified into elytra on 

 account of their habits. " Elytra," he says, " are not an adaptation 

 (Anpasswng) to an a priori protected abode (such as a boring in 

 wood), but to a free abode (Aufenthcdt) on the earth's surface." 

 At the same time this is not entirely convincing. 



* This is apparently meant to include the PseudocorylophiD/E (of which 

 Aphemocephalw is a genus) and Pilenocepiialid.e of Matthews (Corylophidae 

 and Sphseriidte, 1899, pp. 197, 205). 



