Insects 169 



in essential structure, but the lilac form has on the average more 

 gland-pores. Thus we have the insects in a very early stage of 

 evolution, on the way to become recognizably distinct species. 

 The matter is of practical importance, because while the lilac 

 form infests many kinds of trees and shrubs, as ash, poplar, aspen 

 and willow, it does not feed on apple. When specimens of the 

 lilac form were artificially transported to apple and pear, they 



JUm 



H' 



m * larva. 



m * larva.. " v ' 



Aonidie pseudaspidiotus. Caudal end of female and larva. Highly magnified. 



could not survive. It is the lilac form which exists in the Denver 

 parks, and was found by R. L. Shotwell on willow near Boulder. 

 Miss Griswold does not attempt to settle the proper names of the 

 two forms, but it is highly probable that the lilac form is to be 

 called Lepidosaphes ulmi, and the apple form L. pomorum (Bouche) 

 or L. ulmi pomorum. The only uncertainty relates to the precise 

 characters of the European form on elms, which has not been 

 reinvestigated in recent times. 



Many interesting scale insects, some of them of tropical origin, 

 may be found in greenhouses. 



COLEOPTERA OR BEETLES 



When, in 1887, I announced to my friends and relatives in 

 England that I was leaving for Colorado, the nearly universal 

 comment was: "then you'll see the beetle!" The Colorado 

 potato beetle, thus famous across the water, is the Leptinotarsa 

 decemlineaia, discovered by Thomas Say on Long's Expedition. 

 It was observed to feed on the wild yellow flowered spiny Buffalo 



