100 Mr. F. Bal four-Browne 07i the 



Caniera-lucida drawings show tliat the thorax of IT. rufi- 

 coUis, heydeni, and nomax is slightly wider in proportion and 

 that the sides are slightly more convergent, but it is sur- 

 jn'ising how slight in reality these differences are. 



With regard to the form of the elytra I have spent much 

 lime in trying to make caniera-lucida drawings of the different 

 species, but I found that the drawing seldom resembled the 

 model, and that even minute changes in the position of the 

 insect — slight. raising of the anterior or posterior end — gave 

 an entirely different result in the drawing. There is, how- 

 ever, in spite of the impossibility of figuring- it, some 

 difference, perhaps in curvature of surface and light reflection, 

 which is quite indefinable, but which is useful. 



But variations in form occur within a species, and the 

 members of one group approach and sometimes even overlap 

 those of the other. //. nomax, for instance, seems to be 

 specially variable and some individuals are evidently widest 

 across the middle of the elytra. H. ruficoilis and loehnchei 

 also vary somewhat, so that caution is necessary in making 

 use of this character. 



The Elytral Stri^. 



Edwards divides the species into two groups according 

 as "the dark lines 1-4 [are] unequal in width, distinctly 

 widened on the disc, 5-7 interrupted at the base, in the 

 middle, and at the apex, and often confluent," or " 1-4 of 

 uniform width throughout, 5—7 less decidedly or not at all 

 interrupted," and in this character I find some variation, 

 especially as regards H. weknckei and also in H. nomax which 

 was unknown to Edwards. 



It is often very difBcult to determine the females of 

 II. ivehnchei as distinct from those of //. ruficoKis, but males 

 of the former not infrequently show elytral lineation of the 

 same type as that described for the latter, and females, which, 

 on the majority of characters, belong to the former, even more 

 frequently on this character should belong to the latter. In 

 //. nomax the majority would belong to the ''ruficoilis " 

 section, but some have a clear lineation which would place 

 them with the ^'wehnckei^' section, and in this species at 

 least the extent to which the black overflows the lines and 

 runs into patches varies greatly in different localities. 



In all the species there seems to be a tendency for the 

 black lines to break up, but it is, I think, rarest in //. apicalis 

 and //. immacidatus. This character is not therefore of great 

 value in separating the species, although as an indicator it is 

 frequently useful. 



