306 C. E. MCCLUNG. 



ties of chromosome structure which seem to me of considerable 

 importance. Some of these will here be considered. 



It will hardly be necessary to enter into any account of the 

 chromosomes in the Acridian family since this subject has already 

 been discussed in a former paper ('oo). Familiarity with the 

 spermatogenesis of these Orthoptera will, therefore, be assumed 

 and only such details gone over as are new or, at present, better 

 understood. 



The forms upon which the new observations were principally 

 made are three species of the Acridiinaean genus Hesperotettix, and 

 a species of hlcriniria, a Tryxaline. While the facts stated have 

 to do with these forms, they derive their importance from their 

 relation to what appear to be common processes in the groups 

 to which they belong. Much more work is, therefore, involved 

 in the attainment of these results than would appear on first 

 thought, and the basis for theories is correspondingly widened. 

 In addition to the facts gained from the species mentioned, con- 

 firmatory evidence on a number of points afforded by some 

 incomplete observations on Chortophaga viridifasciata, an Acri- 

 dian, and Anabnts, a Locustid 



II. OBSERVATIONS. 

 i . Number of Cliromosomes in the Family Acridida. 



It may be recalled that in previous papers I have not laid much 

 stress upon reported numbers of chromosomes, because of the 

 difficulties involved in securing accurate enumerations. Never- 

 theless the full importance of this knowledge has not lacked 

 appreciation, and latterly more attention has been directed toward 

 the determination of the number of chromosomes in the different 

 species of Acrididae. In order to avoid the operation of the per- 

 sonal factor as much as possible, camera lucida drawings were 

 made in considerable numbers from time to time and laid away. 

 Finally the drawings were taken and the counts tabulated. As 

 only the clearest cases were used for drawing, and as every pre- 

 caution was taken to see that the entire complement of chromo- 

 somes for each cell was present, it is thought that the figures are 

 reasonably accurate. Since this is the judgment of one who has 

 at all times been decidedly critical toward the subject of chromo- 

 some enumerations, it may lend assurance to the results. 



