﻿Dec. 1895] Webster. North American Species of Diaurotica. 1G5 



trations are given of ten of these cases of mimetic resemblances, and it 

 must be confessed that Mr. Gahan has made out an extremely strong 

 point. But one of our North American species of Diabroiica is in- 

 cluded in this list, D. vittata, which is given as the protector of Lema 

 Tiigrovittaia. I have strongly suspected this of our Diabrotica for sev- 

 eral years, but the only case that appeared to me at all probable was 

 that of our Cerotoma caminea, some of the collorial forms of which re- 

 semble D i2-punctata. But Mr. Gahan in his list gives C. arctiata as 

 being mimicked by Lema criicifera, in Cayenne, which if correct, as I 

 am inclined to believe, would render any such relation impossible. Of 

 our seventeen species and varieties of Lema, as included in Henshaw's 

 list, 1 have compared ten with an equal number of our eighteen species 

 of Diabrotica, but shall be obliged to confess that among our North 

 American species of these genera there does not appear to be any 

 mimetic resemblances whatever, at least so far as my comparisons have 

 carried me.* 



Mr. Gahan, with commendable candor, freely admits that fresh 

 observations of the species of the genera Lema and Diabrotica in their 

 living stage will have to be made before it can be definitely established 

 that the resemblances between them are cases of true mimicry. When 

 this has been done, whether we find similar relationships existing among 

 our North American species or not, we shall have ample proof of the 

 inedibility of the species of Diabrotica and thus solved the problem of 

 their protection from attacks of birds, as indicated by the great number 

 of examinations made of the food of many of the most common of our 

 species. 



In conclusion, it would seem as though Central America, Mexico 

 and possibly southern Arizona, southern New Mexico, and perhaps also 

 southern Texas, comprised the womb, as it were, within which our 

 North American species of Diabrotica had been formed and from out 

 of which they had issued. And may it not be possible for the careful 

 student, located within these boundaries, to still witness in Prof. Cock- 

 erell's incerta, variety of D. vittata, LeConte's tenella, variety of 12- 

 punctata, Harold's 12-tiotata or some of the variations of atripennis, the 

 actual evolution of species? A study of this genus of beetles over the 

 area indicated will certainly richly reward the student, and not unlikely 

 bring to light some facts that will prove of immense value to the science 

 of biology in general. 



*This statement has since been verified by examinations of these genera as rep. 

 resented in the National Museum at Washington and the Philadelpliia Academy of 

 Science. 



