APFLE-TRUNK BARK- LOUSE KINDRED SPECIES. 35 



vated currant, but have found it upon our wild currant (Ribes 

 jloridvm,) pretty numerous. Scales very similar to those of the 

 Apple bark-louse, but of a smaller size, of a pale brownish color, 

 and not curved, may be met with also upon the twigs of the but- 

 ternut. Some of these are so small as to be imperceptible to the 

 naked eye. As they are evidently a distinct species, I propose to 

 name them the Butternut Bark-louse, Jlspidiotus Jugldndis. My 

 friend, Dr. A. S. Todd, of Wheeling, Virginia, has sent me speci- 

 mens of another species of this same genus, occurring upon Rose 

 bushes. He says : " My finest roses are cursed with these ver- 

 min. They kill ' for certain ' every Rose bush they get upon. It 

 dies to the ground." This is a round, flattish, white scale, about 

 five hundredths of an inch in diameter, often with a light yellow 

 spot or cloud in its center. This is probably the Aspidiotus Rosce 

 of Bouehe, (Schadl. Gart. Ins., p. 53,) which is briefly noticed 

 in Kollar's Treatise, English edition, page 179. 



The Apple Bark-louse is about one-eighth of an inch long, of 

 an irregular ovoid form, often bent in its middle, and more or 

 less curved at its smaller end, which is pointed, the opposite end 

 being rounded. It is of a brown color, of much the same tint 

 with the bark, its smaller end being paler and yellow. 

 It closely resembles an exceedingly minute oyster-shell 

 pressed against the bark — a similitude so striking as to 

 I be readily perceived by every one, and is frequently 

 l «lWiP> designated in common conversation, under the name of 

 the Oyster-shaped Bark-louse. These shells or scales are situa- 

 ted irregularly, though the most of them are placed lengthwise 

 of the limb or twig, with the smaller end upwards. The^e scales 

 are tlie relics of the bodies of the gravid females, covering and 

 protecting their eggs. During the winter and spring, these eggs 

 may be found on elevating the scales. The number of eggs under 

 each scale is very variable. Several which I have counted, have 

 shown the following numbers— 13, 22, 36, 54, 58, 71, 86, 102. 

 I have uniformly found a greater number of eggs where the scales 

 were upon a thrifty tree When a tree becomes overrun, so as 

 to dwindle and not afford a copious supply of nourishment, the 

 number of eggs is reduced. 



