14 MONOGRAPH I A 



prominent; antenna? about f the length of the head, cylin- 

 drical, rather thick (a) ; thorax elongate quadrate, longer 

 and wider than the head ; its divisions slightly developed 

 with a broad blackish interrupted margin ; abdomen large, 

 elongate ovate, the lateral margin deeply emarginate, the 

 first six segments, with a broad blackish margin in the 

 female, in the male with a black patch only, encircling 

 each spiracle ; legs long, thick, posterior ; femur much 

 enlarged (j). Length $ f , ? U. 



Some little confusion appears to exist between the 

 Synonyms of this, and the following species, which has 

 arisen from the circumstance of nearly all the early writers 

 having considered them as only varieties of the same species, 

 which was denominated Ped. Humarius. Linnseus, how- 

 ever, regarded them with greater precision ; and although 

 he did not designate each by a peculiar name, assigned 

 each its locality, which he considered as constant, and 

 retained the one specific name of humanus. As, however, no 

 doubt can exist as to the Capitis and Vestimenti being 

 specifically distinct, I have ventured to place the majority 

 of the Synonyms to the most common species, the Cer- 

 vicalis of authors, the Capitis of De Geer, as the most 

 probable one which they have been describing, or rather 

 enumerating, for many give no diagnostic characters 

 whatever. And although this is commonly called the Head 

 Louse, and the following the Body Louse, by way of dis- 

 tinction, they possess characters sufficient to identify them 

 more correctly than a name derived from a locality, which 

 I strongly suspect does not invariably hold good. For 

 though the Capitis does, doubtless, prefer the head, and is 

 most commonly found there, especially in those of children, 

 from its being the part most suitable, on account of the 

 greater quantity of hair, yet it. will stray over every part of 



