40 CALIFORNIA ACADEMY OF SCIENCES. 



Macloskie, G. " Grosse's Classification and Structure of the Bird-lice or 



Mallophaga" (abstract), Arner. Nat., 1886, vol. xx, p. 340, ill. 

 Kellogg, V. L. " Notes on the Mallophaga," Transac. Kansas Acad. Sci., 



1889, vol. xii, part i, p. 46. 

 Osborx, Herbert. " Notes on Mallophaga and Pediculidae," Canad. Ent. 

 1884, vol. xvi, p. 197. 



"Note on the Period of Development in Mallophaga," Insect Life, 



1890, vol. iii, p. 115. 

 " Origin and Development of the Parasitic Habit in Mallophaga and 



Pediculidte," Insect Life, vol. iv, 1891, p. 187. 

 "The Pediculi and Mallophaga," Bull. No. 7, Div. of Ent. U.S. 



Dept. of Agric, 1891, ill. 

 " Collecting and Studying Parasitic Insects," Arner. Mo. Mic. Jour., 



1S94, vol. xv, pp. 56-59. 

 "Keys to the Genera of Pediculidaa and Mallophagida?, " Amer. Mo. 

 Mic. Jour., 1894, vol. xv, pp. 344-346. 



Structure. 



External. — The characteristic external appearance of 

 the Mallophaga is due to a structural condition incident 

 to the parasitic habits of the insects. The body is small, 

 wingless, greatly flattened and usually strongly chitinized. 

 There are no indications of wings in any stage of the in- 

 sect's life. 



Head (fig. 7, plate ii). The head is large in propor- 

 tion to the whole size of the bod}-, flat (slightly convex 

 above and slightly concave below), and variously cres- 

 centic, reniform, quadrangular, triangular, narrowly or 

 broadly conical. It is usually sparsely haired, the hairs 

 appearing specially along the acute lateral margins. The 

 mouth parts and oral opening are on the under side of the 

 head; and the antennae are outstretched or concealed in 

 excavations on the under side. The most conspicuous 

 character of the fixed parts of the head, other than their 

 extremely flattened condition, is the great development of 

 the clypeus which usually forms the principal part of the 

 head in front of the antennary insertions, and is prolonged 

 as a flat, tapering or expanding, colored or partly uncol- 



