248 MEMOIRS ON THE COLEOPTERA 



elytron. When these spots and the vitta are greatly reduced we 

 have forms like hogei, when more expanded forms like septentrionis, 

 marginipennis and californicus, and when most developed entirely 

 black forms, such as cethiops and mormonicus; or, when some one or 

 two of the normal features disappear, we have exceptional but not 

 non-typical forms of ornamentation as observable in deflectens, 

 childreni and others. 



Now if Mr. Leng will examine the related European Bmmus 

 8-signatns, he will perceive at once what I mean by type of orna- 

 mentation; for the spots of 8-signatus are in such number, and es- 

 pecially in such position, that by no conceivable variation could 

 they ever assume any such form as in our representatives of Exo- 

 chomus. So again, if Mr. Leng will examine the pronotum of the 

 true Coccinella as typified by Q-notata, for example, and compare 

 it with the pronotum of Olla or Adalia, he will again find a difference 

 which is that of type in the sense which I desired to convey by that 

 term. All our Hippodamice have a common type of ornamentation, 

 excepting the spuria and parenthesis groups and ij-macttlata, 

 which have more or less different types of maculation. ij-macu- 

 lata, abundant near St. Louis, having the post-scutellar spot ex- 

 panded transversely, sometimes simple and sometimes resolved into 

 two spots but never, so far at least as evinced by my series, exhibiting 

 the slightest tendency to unite with the scutellar dash a character 

 so generally prevalent, possesses for those reasons a rather different 

 type of maculation from any of the allies of divergent, showing that 

 it is an isolated species. 



A good many genera as we conceive them now are composite 

 and include diverse elements, some of which do not adhere to the 

 type of ornamentation characterizing the majority of the species; 

 but this only means that these various types indicate very well- 

 marked groups or subgenera of the genus, which we deem it better 

 not to define as subgenera because of the interminable nature of 

 the subject. In Hyperaspis, for instance, a type of maculation 

 appears as in levrati and metator, which is deceptively similar to 

 that prevailing in a large group of Brachyacantha; and many other 

 examples could be cited, such as the European Exochomus 4- 

 pustulatus, the Cuban E. venustulus or the South African E. ver- 

 sutus, when compared with our own forms of the genus; some of 

 them are evidently subgenerically different. 



