•318 REVISION OF THE CICINDELID^ OP AUSTRALIA, 



There are some variable minor characters of merely specific 

 value which seem worth attention and study in the genus Mega- 

 cephala, but for this work my material is insufficient. Such 

 are — (l)The teeth of the mandibles. (2)The underwings present, 

 or not. I regard the underwings as present in the described 

 Australian species except M. cylindrica, M. fren-chi, M. spenceri, 

 M. greyana, and M. cylindrica, but their absolute absence in 

 these species requires confirmation ; and their presence and 

 development in the other species also require attention. In this 

 connection it is to be noted that in the species with unicolorous 

 elytra those which are winged have the elytra less convex and 

 cylindrical, and much more strongly ampliate at the base on each 

 side of the peduncle than those which are without wings. This 

 difference in the amplitude of the elytra between the winged 

 and the wingless species is noticed less along the lateral border 

 than above the border, a result evidently caused by the necessity 

 for a greater dilatation to cover the bases of the wings in the 

 winged forms. Though this is apparently a feature of high 

 importance, and readily noticeable, it has not appeared to me 

 very suitable for tabulation purposes, the differences being merely 

 of degree; and differences which are not trenchant are generally 

 unsatisfactory in tables, as liable to misinterpretation. (3)The 

 relative length of the posterior femora as compared with the 

 abdomen seems to me merely of specific value, there being all 

 degrees of length; in the species with short posterior femora the 

 posterior trochanters do not extend behind the posterior margin 

 of the third ventral segment. (4)The form of the two basal 

 ventral segments varies; the first segment is triangular in M. 

 cylindrica, and with inner part much narrower and more extended 

 in M. crucigera; there seem all degrees of difference between 

 these forms ; the second segment is much longer, especially 

 behind the posterior coxal cavities, in M. cylindrica than in the 

 wider-bodied winged species. (5)The distance between the inter- 

 mediate and posterior coxae varies; it is shortest in M. howitti, 

 M. greyana coming next; it is merely a specific difference. 



