﻿THE CATTLE GEUBS OE OX WAEBLES 



47 



posited along the back of the thighs, on the escutcheon (fig. 22), 

 or on the base of the udder. A number of instances have been 

 observed where the soreness and s^Yelling extended down the rear 

 quarters to the udder and the tenderness made milking difficult. 



Beneath the skin these swellings are similar in appearance to 

 the " licked-beef " condition ordinarily found along the back when 

 the last-stage larvse reach that region. The connective tissue around 

 the point of penetration is edematous, tinged with yellow, and some- 

 times slightly bloody. 



The scabs become dry within a few days and can be removed. 

 Usually a small quantity of hair comes off with them and a num- 

 ber of pits are left, in the skin indicating the points where the 

 larv8e have penetrated. If the scabs are not removed artifically 

 they disappear in the course of a week or two. Animals slaughtered 

 during the period of larval penetration have the hides more or less 

 damaged at points where 

 the larvEe penetrate, and 

 slight infiltrated areas are 

 visible on the carcass. 



As has been stated by 

 other writers, these lesions 

 may serve as portals 

 through which disease or- 

 ganisms, such as anthrax 

 or tuberculosis, may enter. 



The actions of the ani- 

 mals at the time the larvse 

 penetrate have been men- 

 tioned in a general way. 

 The first inclination of an 

 animal, after penetration 

 on the heel begins, is to 

 shake the foot. This is 

 usually followed by licking 

 (fig. 23), which "^is often 

 very vigorous and pro- 

 longed, and animals have been observed to continue it for tw6 

 minutes without stopping. When the individuals are not allowed to 

 lick the heels they usually twist, squirm, kick, and stamp, thus 

 showing marked pain or irritation. 



OCCURRENCE IN THE GULLET AND BODY CAVITY 



On account of the minute size and ti anshicent appearance, it is not 

 surprising that various investigators have been unable to observe 

 tlie course followed by the first-stage larvoc after penetration of the 

 skin. Stub ('9-5), working in Copenhagen, has given us the only 

 definite record. In a |>ost-mortem he observed an infiltrated area 

 in the supei-ficial connective (issue on the inside of the right tibia, 

 and succeeded in following the track over tlie shoulder, around the 

 muscles of the neck tr) the tissue on the esophagus, where it enlers 

 the thoracic cavity. IFcic he found a number of lar\'ie in close 

 proximity and measuring 1 to 2 millimeters in length. Jladwen {'lO) 



Fig. 22. — Lpsinns on escutcheon of cow, caused by 

 peDetratioii of newly-hatched larvse of Hypoderma 

 lincatum 



