546 MEDICAL ENTOMOLOGY 



lateral borders of the abdomen are less festooned. The statement made 

 by Piaget, and repeated after him, that there are seven segments in the 

 abdomen of capitis and eight in vestimenti, is incorrect, as there are eight 

 segments in each. None of these points is very definite, and variations 

 in the particulars noted above are to be found in lice from either the 

 head or the body; the authors have to confess that in many instances 

 they have found it impossible to decide whether a given specimen should 

 be regarded as capitis or vestimenti. 



GENUS PHTHIRUS, LEACH 



Forelegs with very long and thin claws. The remaining legs very 

 strong with short and thick claws. Thumb-like process on the tibia short 

 and stout. Abdomen very short and broad. The first to the fifth seg- 

 ments of the abdomen are very strongly compressed, so that the stigmata 

 of the first to the fifth segments appear to lie in one segment. Fifth to 

 eighth segments with lateral tooth-like processes, the penultimate long, the 

 last very long. (Dalla Torre). 



This genus contains the single species pitbis, L., the pubic louse (Plate 

 LXVI, fig. 1). It is distinguished at once from the other pediculi which 

 occur on man by its characteristic body form. The thorax and abdomen 

 are compressed together to form a heart-shaped mass, broadest in front ; 

 the abdominal segments are narrower than the thoracic ones, and diminish 

 in breadth from before backwards. The short squat flattened body and 

 the powerful middle and hind legs have given it its popular name of 

 ' crab ' louse. As its specific name implies, it is usually found about the 

 pubic region. It is not so common, or so easy to procure, in Madras as 

 the head and body lice. 



GENUS PEDICINUS, GERVAIS 



The general characters of this genus are those of the Pediculidae, with 

 the exception that the antennae have three joints instead of five.* Three 

 species are recorded, all from monkeys, as follows. P. enrygaster, 

 Gervais, from Macacus sinidus ; longiceps, Piaget, from Cercopithecus 

 mona ;piageti, Stroebelt, from Macacus erythraens. Pedicinus enrygaster, 

 from the Madras monkey, Macacus sinicus, is shown on Plate LXVI II. 



* This statement is made by Enderlein, and repeated by Dalle Torre. Examination of 

 fresh and cleared preparations, however, shows that the terminal joint, which is much longer 

 than the other two, is ' ringed ' in two places, each annulation having a circlet of short and 

 fine hairs. It is, therefore, a matter of opinion as to whether there are three joints or five. 

 The drawing was made from a mature female, and is correct as regards the appearance of 

 the antennae. The shape of the body offers a much more evident distinction between the 

 two genera. 



