E. H. STRICKLAND. 



inn. the cuticle over this disc ruptures and liberates the fully 

 formed and now functioning filaments. 



The growth of these various histoblasts causes the thorax 

 to >well considerably, thus giving the body the appearance of 

 being const rioted in the middle. 



Internally there is comparatively little tissue. The abdomen 

 contains the alimentary tract, and the much elongated salivary 

 glands which lie normally in a ventro-lateral position with regard 

 to the alimentary tract. The sexual organs are small and not 

 ea-ily found even in serial sections. The remaining portions of 

 the body cavity are filled with blood plasma in which is suspended 

 a quantity of fat body, mainly collected near the apex of the. 

 abdomen and causing this region to become slightly swollen. 

 As the larva- mature this fatty tissue very materially increases, 

 and when dissected out, is of a stringy nature. 



METHODS. 



Most of the larvae were killed as soon as they were brought 

 into the laboratory, but a few of the more heavily parasitized 

 ones were kept, alive in running water by covering the mouth of 

 a jar with fine net I ing and introducing a piece of rubber pipe into 

 the jar, through which tap water was run. In this manner 

 -pecimens were kept alive for several days. 



The following killing fluids were found to be the most satis- 

 factory among several tried: 



1. JI<>! Water. Water was just brought to the boil when the 

 lar\;r were immersed and allowed to cool in the water. This 

 method was most unsatisfactory from a histological point of 

 view, but it had the advantage of leaving the skin as transparent 

 as in its normal condition. It was also possible to dissect larva- 

 thus killed. 



2. Ci il son's Fluid. This was used hot as described above and 

 gave good n-Milis, but had the disadvantage of making staining 

 with the haematoxylins difficult. 



; v Kalile's Flu id, consisting of 30 parts water, 15 parts 96 

 per cent, alcohol, 6 parts formalin (40 per cent.), I part glacial 

 acetic acid. This fluid has been recommended by W. Kalile 

 (1908) and proved to be superior to Ciilson's fluid both for 



