70 Mr. P. Koorevaar on the 



visible in specimens preserved in spirit tlian in the fresh 

 larvas. 



The dimensions of these spinal larvfe vary considerably ; 

 in a collection that I formed between October and February 

 there is one specimen measurino^ 5 millim. in length by 

 ^ millim. in breadth ; the remainder are from 6 to 14 millim. 

 long and from 1 to 2^ millim. broad. 



In the warm fat, before it has become solid, the larvaj lie 

 extended ; if they are set free they assume a curved shape 

 and contract, becoming in consequence considerably shorter 

 and thicker; in this contracted condition the annulations are 

 also distinctly visible. As regards other details these grubs 

 have the characteristics of (Estrld larvse. 



In the year 1884 M. Hinrichsen, a veterinary surgeon, in 

 dissecting a tuberculous bullock, found the first specimen of 

 these larvffi in the spinal canal ; in 1888 he publisiied in tlie 

 * Archiv iiir wissenschaftliche und praktische Thierheilkunde,* 

 Bd. xiv., an account of the examination of thirty-nine cattle. 



]n the case of fourteen of these (for the most part the 

 younger animals) he met with from one to twenty larva? in a 

 portion of the vertebral column. So long ago as I8f)3 

 Prof. Brauer described and figured these larva; in l)is * ]\lono- 

 graphie der CEstriden,' but the fact that they occur in numbers 

 in the spinal canal was nevertheless new. 



Further statements as to the finding of these larvre in the 

 neural canal in cattle are also given by Hinrichsen, Home, 

 and Eustr in the 'Zeitschrift fiir Fleisch und Milchhygiene ' 

 for 1895. 



Hinrichsen considered these (Estrus-\t{r\2e. to be the first 

 stage of JJi/poderma hovis, which was till then unknown ; 

 and Prof. Brauor agreed with this ojjiiiion. 



Owing to the hequent occurrence of this larva in the spinal 

 canal Home was led to consider the latter as the normal 

 hidden resting-place of Hypoderma hovis. 



In the middle of January I n)et with the first specimens of 

 BypoderihaA'AWfn beneath the skin ; on a closer examination 

 ten more Cfi/re/s-larva} were found in the epidural fat of the 

 vertebral canal. 



The occurrence of ITt/podcrma-\i\\\K, beneath the skin, in 

 what are known as warbles, and at the same time of (Eatrus- 

 larva? in the spinal canal in the same animal, was repeatedly 

 observed in the months of January, February, and March in 

 the slaughtered cattle at the abattoir. 



It is remarkable that in size and form the largest spinal 

 larvai do not difl'er from the youngest JIt/j>oder}7ia-\arvse in 

 the subcutis ; the subcutaneous lar\ae are somewhat less 



