38 
LOUSE OF THE SHELDRAKE. 
{Lipeurus tadornce Denny; Lipeurus lacteus Giebel.) 
Denny described this species from specimens taken from the shel- 
drake, and cites also a manuscript name of Leach, Ornithobius tadornce, 
which he assumes to be the same and which applied to specimens in the 
British Museum. The species was later described by Giebel with the 
name lacteus, though he at the same times quotes Denny's name without 
stating any reason for the change. 
Piaget states that he prefers the name chosen by Giebel to that of 
tadornce in order to avoid as much as possible the names of birds upon 
which the parasites have been found. If this principle were carried out 
it would involve the change of hosts of names applied to members of 
this group of insects, and as it is directly opposed to the well-estab- 
lished principle of priority we believe the name applied by Denny 
should be restored. 
The insect is characterized by a milky- white color, the surface smooth 
and shining, the head, thorax, and abdomen with black marginal spots; 
it is elongate in form and the head heart-shaped. 
Professor Comstock cites it as occurring also upon the goose, but upon 
what authority we are unable to say, as the authorities consulted men- 
tion it only as a parasite of the sheldrake. 
THE PIGEON L1PETJTBUS. 
{Lipeurus baculus Xitzsch.) 
This is another of the species that was given a name and figure in 
the work by Eedi more than 200 years ago. It was also described 
briefly by Linne under the name of Pediculus columbae, but since the 
description by Nitzsch in 1818, under the name of Lipeurus 
baculus, this has been the accepted name, and has been used 
by nearly all writers since that time.* It is not strange 
that it attracted the attention of early naturalists, as it 
occurs in wonderful abundance on almost every pigeon 
that may be examined, and its striking appearance, due to 
the extreme slenderness of the body, would at once catch 
the eye of the observer. 
It is about 2 millimetres in length, the body very slen- 
der ; the head and thorax are of a bright reddish-brown 
W7HY ' color, while the abdomen is rather dusky with a series of 
fig. 26._Li- patches of a brown color corresponding with the segments 
peurug bacu- „ , , , , 
to*. (Original.) of the abdomen. 
*Giebel names and describes two species, bacillus and baculus, referring both to 
Nitzscb, and placing under bacillus the form which all other authors refer to baculus, 
and referring to baculus a form not separated by other authors, but which he de- 
scribes as different from the other form. It seems undesirable to add names without 
a more decided difference in form, and we agree with Piaget in uniting both under 
the old name. 
