June, I9I2.] Wheeler: Xotes ox a Mistletoe Axt. 131 



Pscudococcus phoradendri sp. nov., are in all probability one of the 

 causes of the wilting and dying of the mistletoe. 



On consulting the literature I find that a very keen observer, Mr. 

 E. A. Schwarz, has anticipated some of the preceding observations in 

 a short paper published several years ago.' Speaking of the mistletoe 

 on the trees of Bear Canyon, near Ft. Lowel, at the foot of the Santa 

 Catalina Mts., Arizona, he says: "The rnajority of the more access- 

 ible mistletoe bushes proved to be more or less infested by Lccanium 

 phoradendri and, in many instances, plants had been killed by the 

 prevalence of the scale. A search for Coccinellid enemies produced, 

 after considerable exertion, only a few specimens of Cephaloscymnus 

 occidcntalis Horn. Occasionally mistletoe branches, either not or but 

 feebly infested with scales, were observed to be dead or wilting and 

 it was found were hollowed out for a distance greatly varying in 

 length, according to the thickness of the twig. The author of these 

 galleries proved to be a Curculionid larva of the genus Otidoccphalus, 

 the particular species being still undescribed. The beetle makes its 

 exit through a round hole at the side of the twig, and the deserted 

 gallery is then usually occupied by a colony of ants, Crcmastogastcr 

 sp., which attend to and protect the Lecaniiim scales. 



" The infested twig is not killed at once by the boring of the 

 Otidoccphalus larva, but reiuains green for one season or longer, 

 but at any rate long enough to allow colonies of a Scolytid beetle to 

 undergo one or two generations in the terminal portion of the twig. 

 This Scolytid, one of the smallest of our fauna, is also undescribed, 

 and belongs, as far as I can make out at present, in the neighborhood 

 of Stcphanodcnts. It is an ' inside borer,' but no regularity whatever 

 can be observed in the tiny galleries, nor could one find any trace of 

 ' ambrosia.' The colonies are extremely populous, a single one con- 

 taining between seventy and a hundred specimens, but the males 

 appear to be just as rare as in Xylchorus." 



Schwarz also mentions a Bostrychid larva (Amphiccnis sp.) 

 which bores in the mistletoe stems and a Lyc^enid larva (Thccla 

 halesiis) which feeds on the leaves. 



There can be little doubt that similar phenomena were observed 

 both by Schwarz in the Santa Catalina Mts. and by myself in the 



^ " On the Insect Fauna of the Mistletoe," Proc. Ent. Soc. Wash., Vol. IV, 

 1901, pp. 392-394- 



