176 

 known to Blanchard), while the nabelhim of Phyllococerus 

 has only three joints. I am of opinion that neither the num- 

 ber of joints in the antenna or its flabellum, nor the form 

 of the clypeal outline, is a character of more than 'specific 

 value among the Australian Sericoides, and therefore must 

 regard Phyllococerus as a synonym of Colymbomorpha. The 

 tabulation in Trans. Roy. Soc, S.A., 1905 (p. 281), differ- 

 entiates these insects and Stethaspis from the other Aus- 

 tralian Sericoides. The former two are from Western Aus- 

 tralia. 



The third genus referred to above (Stethaspis) is really 

 very close to Colymbomorpha, but the different facie® and 

 very much larger size of its species differentiate it strongly, 

 for practical purposes. It is not so easy, however, to indicate 

 a good structural difference. Burmeister, as mentioned 

 above, merged Colymbomorpha in Calonota, and stated the 

 number of its antennal joints (incorrectly) as eight. He dis- 

 tinguished it from Stethaspis on that character. Lacordaire 

 placed the two genera in distinct "subtribes" of Melolon- 

 thides, attributing Stethaspis to the "true Melolonthides" 

 which was certainly a mistake, as its ventral segments are 

 certainly not formed as in that subtribe, nor are its front 

 coxae transversal. Blanchard placed Stethaspis in the Rute- 

 lides, quite incorrectly, since the claws of its species are not 

 unequal. There can be no doubt that Burmeister was right 

 in placing it near Colymbomorpha in the Sericoid group. It 

 is, however, distinguished from Colymbomorpha by the first 

 four joints of its tarsi being fringed beneath more or less 

 closely with long hairs and the apical joint with stout bristles. 

 This is, I think, a valid generic character in the Australian 

 Sericoides. It may be added that in Colymbomorpha the 

 labrum projects beyond the clypeus, so as to be visible from 

 above, while in Stethaspis it is completely hidden (viewed 

 from above) under the clypeus. This, however, is riot in 

 itself a valid generic difference in the Sericoides. 



STETHASPIS. (i) 

 So much mention has been made of colour in the original 

 descriptions of the species of this genus, and the species are 

 so variable in colour, that it is difficult to arrive at any clear 

 appreciation of the distinctive characters. All the Australian 

 species except nigrescens, Blanch., and Icetus, Blanch., are 

 described as (< olivaceus," or "olive-green." Lcetus is called 

 u totus Icete vividi-flavescens," and is said to have green legs. 



(i) In Ann. Nat. Hist., 1903, p. 303, Mr. Arrow showed con- 

 clusively that the name Xylonchus used for this genus by 

 Lacordaire and other authors (also in Masters' Catalogue) is a 

 synonym of Stethaspis. 



