205 



nected. The large chrysalis skin roscmhles Cecropia. The cocoon 

 observed at Quebec by Mr. Couper, -which from its likeness to that 

 of Cecropia, he took to be that insect, i)roduced in due time Colum- 

 bia. This cocoon must have been dillerent from all I have seen, 

 which agree exactly with Mr. Smith's description. The cocoon of 

 Columbia is much smaller and of more regular form; dark brown, 

 approaching black in some places, Avitli silvery spots; the inner and 

 outer cocoon so closely Avoven together, except at the very top, as to 

 be separated with difficulty. 



It is fair to state and in disfavor of my above given opinion, that 

 all the cocoons of Columbia are alike, and differ strongly from those 

 from all other species, by the so-called silvery spots, and the dark 

 blackish brown color of the cocoon. The silvery spots are produced 

 by white silk woven around at certain intervals, but crowded to- 

 gether on the spots. 



I draw attention to the fact that the cocoons of Cecrojna, are 

 themselves very variable in form and texture, and one presented by 

 Mr. Smith from the same locality with Columbia, in certain ways 

 approaches the cocoons of Columbia. The silk is the same, but 

 less coarse and not silvery. I confess frankly that only the peculiar 

 features of the cocoons support the opinion that Columbia is a dif- 

 ferent species. 



Concerning the parasites of the large Attaci from New Eng- 

 land, I know eight ; one Dipteron, the Exorista leucaniae var. cecro- 

 piae bred by Mr. Trouvelot from Poh/jjliemus, by Mr. Eiley from 

 Cecropia; the others all Hymenoptera. The large Ophio7i macrn- 

 rum, has been bred from Cecropia by Mr. Eiley and Mr. Altum, of 

 Europe, from Polyphemus by Mr. Trouvelot, from Promethea by 

 myself. In the museum collection I found cocoons, probably be- 

 longing to the southern species S2)lenclidus, also infected by the same 

 Opliion. 



Two species of Crijptus are, without doubt, the most common 

 parasites, C. nuncius Say, and C. Samiae Packard ; with the latter 

 species C. extrematis Cress, is identical. The C. nuncius was bred 

 from Promethea by Say, and in large numbers by myself; from 

 Polyphenms in large numbers by Smith. The C. Samiae has been 

 bred by Smith in large numbers from Cohimbia, and from Cecropia 

 by Smith and Ililey. The two species are very nearly related one 



