526 CLARENCE E. McCLUNG 



8, the complex is strictly of the Hippiscus type. There are 

 neither multiple nor atelomitic^ 1 chromosomes. It is pos- 

 sible that a more extensive series might show some variation, 

 but this is doubtful. If multiple chromosomes are characteristic 

 of the genus — ^w^hich might fairly be said from their prevalence 

 in the species so far studied — then brevipennis departs here 

 from the type. Since this paper deals only with the question of 

 multiple chromosomes, no further consideration will be given to 

 species in which they are absent, except to note that the seriation 

 in size is uniform. 



5. The complex of H. festivus 



This striking and characteristic species, of which numerous 

 specimens have been studied, is like brevipennis and shows no 

 trace of multiple chromosomes. The nature of the complex in 

 the first spermatocyte may be observed in plate 1, complex 2. 

 It seems therefore to have no immediate bearing upon the sub- 

 ject of the present discussion. 



6. The complex of H. viridis 



This species, like speciosus and pratensis, may possess a 

 multiple chromosome, a hexad, constituted of a tetrad joined to 

 the accessory chromosome dyad. The euchromosome portion is 

 larger than those of the other species. This was the condition 

 present in the first specimens which I studied and which served 



1 H. viridis. In a former paper I found it convenient to refer to various 

 forms of chromosomes and to note that their forms depend upon the fiber at- 

 tachment. Following de Sinety, the position of this attachment was designated 

 as terminal, subterminal, or median. In the case of the annular chromosomes 

 terminal attachment apparently results in rings whose plane in metaphase coin- 

 cides with that of the equatorial plate, while with subterminal, or median, at- 

 tachment the rings are so placed as to lie parallel with the spindle axis. For 

 convenience these were spoken of as the Hippiscus type and the Stenobothrus 

 type respectivel}^ With the discovery of additional complexity of forms it has 

 been found desirable to have general terms for the two conditions represented 

 by the ring chromosome, and so it has been agreed in this laboratory to speak of 

 chromosomes with terminal fiber attachment as 'telomitic,' while those with 

 non-terminal attachment receive the name of 'atelomitic' These terms may 

 therefore be used to designate chromosome conditions similar to, but more 

 general than, the ones involved in the two types of ring formation. 



