314 REVISION OF THE CICISDELIDjE OF AUSTRALIA, 



I believe the presence or absence of these setge to be constant 

 in every species: therefore, they may be useful in helping to 

 determine affinities. Often the seta is rubbed off, but then the 

 puncture from which it rises may be seen by a careful examina- 

 tion These setse must have an important functional utility to 

 the insect, but this is a subject on which I know nothing. The 

 objection to the use of these tactile setse in taxonomy is that too 

 much stress may be laid upon the mere absence of one or more 

 of them in a species. Negative evidence is always to be taken 

 cautiously, as of less value than positive evidence; and it may be 

 expected that any of these setse may be lost in a species, all the 

 congeners of which show such a seta; therefore, only when the 

 absence of any tactile seta or setse occurs throughout a group of 

 species or a whole genus, and is supported by other characters 

 of taxonomic value, can one feel confident that such loss of a seta 

 or setse is of more than merely negative importance. Occasionally, 

 in species which have lost a seta, specimens may be found in 

 which such seta is present; e.g., a single specimen of Megacepjhala 

 cruciyera in my collection has the seta of the intermediate 

 trochanters present, though in no other case have T found a 

 Megacephala with a seta on any of the trochanters; this i& 

 evidently a case of atavistic reversion, and of interest as showing 

 that the ancestral form from which Megacephala is descended 

 had tactile setse on the trochanters. 



Some primitive characters. — Some characters may be noticed 

 which, being found in the Megacephalini and Cicindelini, are 

 evidently of ancient origin. Such are — (l)The pubescence of the 

 outer side towards the apex of the intermediate tibise in the male; 

 this is not found in the genus Distypsidera, nor in the Cicindelce 

 spuria*, of this paper. (2)Last ventral segment emarginate at 

 apex in the male;* the notch is sometimes lost in the genus 

 Megoxep>hula. (3) A subsutural row of fovese on the elytra. 



* The old authors described the Cicindelidee as having seven ventral 

 segments in the male and six in the female. The modern view is that the 

 so-called seventh segment of the male is only part of the genital armature. 



