1890.] F.XTOMOLOGICAL NEWS. 



prevalent in the mountains and to the north, while blue is a south- 

 ern characteristic. This, however, is not an invariable rule. In 

 H. ignita there is a regular geographical sequence southward from 

 golden through green to blue. The cupreous and greenish varie- 

 ties of H. chalybea mentioned by Dr. Horn I regard as atavisms. 

 Here, though, it becomes necessary to define one's notion of 

 atavism. Commonly, it is said t<> IK- reversion to the state of an 

 ancient progenitor. Some confine it to the development of half- 

 forgotten rudiments, but to me this seems an unwise restriction. 

 To me there are two fundamentally different kinds of atavism : 



(1) Due to the development of structures now obsolete. 



(2) Due to arrest of development and consequent resemblance 

 to a less-developed or differentiated ancest< >r. 



The first class is due to abnormal development, the second t< > 

 abnormal arrest of development two very different things. Our 

 atavistic green Haltica chalybea clearly belongs to the second 

 division. The first division is exemplified in a horse that develops 

 extra toes. 



.Mr. T. H. Hall gives me a list of his varieties of Donacia 

 sericea. The females are coppery, brassy and green. The males 

 are green, violet and purple. Here we see in the female the older 

 type of coloration to what obtains in some butterflies and other 

 insects. 



At Chislehurst, in England, I collected two species of metallic 

 Chrysomcln\ C. gocttingensis, which lived concealed at the ro.it> 

 of herbage, was dark blue. C. hyperici, on Hypcriciim, and 

 more exposed, is green. Here seems protective adaptation to 

 circumstances; or perhaps we may say that C. hvpcrici would 

 have developed in time to blue, but natural selection prevented it. 

 C. goettingcnsis has beautifully pink wings, but these need not be 

 considered in the present connection. 



Dr. Hamilton found a variety of Calosoma r.v'Av.v/, varying 

 from its normal -r<---n and golden to purple-black, with the mar- 

 gins of thorax and elytra purple-blue. Possibly this was a token 

 of the future color of C. .v/Av.iv. In ('<ini/im we ha\ e ( '. nit ens 

 with something the color of C,i/. ,v//MU7, and the coloring ot 

 Dr. Hamilton's variety is a permanent institution in ( '. :'ii>/tnrns. 

 A. !'.< r-e found he could actually manipulate the>e color change-, 

 in ( '(tntbi/s by chemical means, and produce certain "varieties" 

 at will. 



