352 



THE ANIMAL PARASITES OF MAN 



points out, the characteristics of these larvae do not entirely 

 correspond with those of Leptus autumnalis. Megnin has recently 

 found the larvae of various Trombidia on mammals and human 

 beings (1897), whilst Brucker regards the larvye of Trombidium 

 gymnopterum as Leptus (Rouget). The old opinion which has 

 recently been revived that Leptus is the larva of Tetranychus 

 telarius is entirely without foundation (von Hanstein). 1 



On the skin of man Leptus, as a rule, produces itching and redness 

 (autumnal erythema); sometimes also 

 circumscribed flat wheals, the eruption 

 of which is accompanied by slight fever. 

 These symptoms, however, disappear 

 after a few days. It has been proved 

 that the animals injure the skin and 

 plunge their long hypopharynx into the 

 wound, which occasionally is situated at 

 the orifices of the sebaceous and sweat 



'/ivy 



FIG. 228. Leptus autumnalis, with the 

 so-called suctorial proboscis (after Gudclen). 

 (Magnified). 



FIG. 229. Leptus autumnalis, 100/0. 

 The so-called proboscis is formed 

 around the hypopharynx sunk into 

 the skin. (After Trouessart.) 



glands, in order to suck up blood with it. Around the stiletto-shaped hypo- 

 pharynx a cylindrical tube, annularly thickened at the free end (fig. 229), is 

 then formed by the host ; this has hitherto been regarded as the proboscis of 

 the Leptus ; but as a matter of fact it belongs not to the parasite, but to 

 the host, in the same way as the ramified chitinous tubules that arise in 

 arthropoda as consequences of the bite of mites (Flogel, Trouessart). - 



1 \Tetranychus telarius is well known in all its stages as a vegetal pest. There 

 is no connection in any way between it and the harvest bug. F. V. T.] 



- Kuchenmeister, F., " Ueb. d. sog. Stachelbeer-oder Erntemilbe " (Varga's Zeitschr. 

 /. Med. Chir. u. Geburtsh. N.F.L," 1862, i., p. 289); Gruby, " Herbstery theme " (Attg. 

 Wien. med. Ztg., 1861, p. 19) ; Gudden, " Ueb. eine Jno. v. Lept. aut." (Arch. f. path. 



