258 Annals Entomological Society of America [Vol. VI, 



The post-sutural dorso-centrals and achrosticals in L. 

 sericata form a group of twelve in four rows of three each as 

 shown in the diagram (Fig. 1). This arrangement is recorded 

 as 3, 3, 3, 3, the separation into rows being denoted by 

 commas. 



Fig. 1. Thorax of Calliphora viridescens to show 

 typical arrangement of post sutural bristles. 

 1. Transverse suture. 2. Supra-alar bristles. 

 3. Intra-alar bristles. 4. Dorso-central bristles. 

 5. Post acrostical bristles. 6. Scutellar suture. 



When one or two of the anterior bristles of a row are omitted, 

 the row is denoted by 2 or 1 respectively. 



In order to denote the omission of the second or third bristle 

 when those anterior to it are not omitted, the -normal positions 

 of the bristles are recorded as a, b, and c, from anterior to 

 posterior. Thus a row lacking the second bristle would be 

 called ac. 



Addition of a supernumerary bristle into a row is denoted by 

 ! inserted in the proper position between or in front of the 

 letters denoting the normal bristles. Thus addition of a bristle 

 in front of a row would be expressed by calling the row !abc. 

 But in some cases the number of bristles alone was recorded 

 for each row and the row was called 4 or 5, according to whether 

 ' one or two bristles were added. 



Insertion of a supernumerary bristle between the normal 

 rows is denoted by parentheses enclosing a, b, or c, according 

 to the position of the bristle from anterior to posterior. Thus 

 a definition as 3, (a), 3, 3, 3, would denote the addition of a 

 bristle between the first left post-dorso- central and the first 

 left post-achrostical. 



Additional bristles are usually smaller than the normal, 

 but range all the way from microchaetse to the size of the 

 normal macrochaet£e. A small bristle is denoted by italics. 



The records of wild files are first noted, and these are fol- 

 lowed by an account of the breeding experiments. 



