uniting into one. The chylus-stomach is cordate at its beginning, — 
rs 
346 Grosses Classification and Structure of the Bird-lice. [ April, 
as the last is invaginated so as to serve as a sheath for the penis; 
the hind end of the male is pointed and more chitinized, and 
more darkly colored than in the female. 
Digestive track—Two types of crop are found in the Mallo- 
phaga. In Philopterida the crop is a lateral diverticulum of the 
cesophagus; in Liotheidz it is a club-shaped symmetrical enlarge- 
ment of the cesophagus. Kramer divides the intestine of Lipeu- 
rus into an oral-cavity, an cesophagus, crop, chylus-stomach and 
hind-intestine. The cesophagus reaches back to the abdomen, 
and has a homogeneous chitinous intima. The intima of the 
crop has spines, and its cells appear to secrete a fluid. The chy- 
lus-stomach extends to the entrance of the malpighian tubules. 
Grosse finds in the cesophagus of Tetrophthalmus, behind the 
_ hypopharynx, a chitin-bar produced by thickening of the intima, 
consisting of a groove-like mid-piece, and running forward and 
backward into two diverging branches. The hind branches have 
muscles from the occipital border of the cranium. These chitin- 
ous bars are not haustellate, but support the oral intima, and in 
their groove are sent along comminuted fragments of feathers, 
retained by the retrorse spines and denticulations of the do 
part of the intima. 
Goniodes has two squamous cesophageal pieces, a dorsal and a 
ventfal (Fig. 2, ds, vs). The ventral piece has posterior processes 
joined by muscles with the occipital border. The dorsal piece 
sends forward a muscular bundle, which bifurcates and its divi- 
sions are inserted on the anterior cranial border. Two ducts 
(probably salivary) run forwards through these scale-like pieces, 
and has no chitinous intima. The hind-intestine has six longitu- 
dinal grooves, and rectal glands with richly branching trachee 
and a chitinous intima. 
The mode of nutrition of Mallophaga is not fully ascertained. 
Nitsch stated that they eat the epidermal products of birds and 
mammals, and sometimes blood. Grosse finds that blood is 
~ rarely taken, and only in cases where the bearers (birds) are 59 
_ injured or diseased as to have blood among their plumage; an 
Leuckart gives the same result as to Trichodectes canis of 
dog. In Lemobothrium, Grosse found the intestine filled with 
the limbs of its own kind, as if it ate the product of its own 
> 
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