260 INSECT A. 



Quadrupeds. That which lives on the Kog has a very narrow tho- 

 rax with a very wide abdomen, and forms the genus Hsernatopinus, 

 Leach(l), the Pou du Buffle, figured by De Geer, Insect., VII, 1,12, 

 presents more important characters. 



The others Nirmidia, Leach such as the 



Ricinus, De Geer Nirmus, Herm. Leach, 



Have the mouth inferior, and composed externally of two lips and 

 two mandibles, resembling hooks. Their tarsi are very distinct, 

 articulated, and terminated by two equal hooks. 



One single species excepted, that of the Dog, they are all exclu- 

 sively confined to Birds. Their head is usually large, sometimes tri- 

 angular, and at others forming a semi-circle or crescent, and fre- 

 quently presenting angular projections. It sometimes differs, like 

 the antennas, in the two sexes. I have perceived, in several, two sim- 

 ple approximated eyes on each side of the head. According to the 

 observations of M. Savigny, communicated to me by himself, these 

 animals are provided with jaws, each of which has a very small 

 palpus, hidden by the lower lip, which has also two organs of the 

 same description. They have moreover a kind of tongue. 



M. Leclerc de Laval informs me that he has found parcels of fea- 

 thers in their stomach he thinks that they constitute their only food. 

 De Geer, however, assures us that he has found the Pediculus of the 

 Fringilla ccelebs filled with recently imbibed blood. It is well known 

 that these Insects survive but a short time on dead Birds. When 

 thus situated, they are observed to wander over their plumes with 

 much anxiety, those of the head and the vicinity of the beak espe- 

 cially. 



Redi has also represented a great number of species of this sub- 

 genus. 



The mouth of some is situated near the anterior extremity of the 

 head. The antennae are very small, inserted laterally, and at a dis- 

 tance from the eyes(2). 



In the others, the mouth is nearly central; the antennas are placed 

 close to the eyes, and their length about equals half that of the 

 head(3V 



(1) Zool. Miscell., CXLVI; P- suis, Panz., Faun. Insect. Germ. LI, xvi, 1. 

 The P. cervi, Panz., lb., xv, belongs to the genus Melophagus, of the Dip- 



tera. 



(2) Pediculus sternsc hirundinis, L.; De Geer, Insect., VII, iv, 12; Ped. corvi 

 coracis, L. ; De Geer, lb., ii; Ricinus fringillsc, De Geer; lb., 5, 6, 7; Ped. tin- 

 nunculi, Panz., lb., xvii. 



(3) Ricinus gallinse, De Geer, lb., 15 on the Cock, Partridge, and Pheasant; 



