268 MARY T. HARMAN. 



Robertson ('15) says: "In the Tettigidae (Tettiginse) a sub- 

 family of the short-horned grasshopper family Acrididse, I have 

 found for all the specimens of at least four different genera which 

 I have examined the number of chromosomes to be uniformly 

 14 in the female and 13 in the male." 



From the above data one would scarcely be justified in saying 

 that the characteristic number of spermatogonial chromosomes 

 of the subfamily Tettiginae is thirteen but the writer feels justified 

 in saying that this is an essential variation in the number of 

 chromosomes given in the above quotation from McClung as 

 the number characteristic for the family Acrididae. The writer 

 has found no indication of multiple chromosomes. 



In the prophase tetrad six of the chromosomes are always 

 dumb-bell-shaped and one ovoid. There are none of the irregu- 

 lar shaped chromosomes as described by McClung and no in- 

 dications of the annular chromosomes which he says "that 

 practically without exception every investigator of recent years 

 who has made a careful study of the maturation stages in the 

 Orthoptera has seen and figured." If the dumb-bell-shaped 

 chromosomes are similar to his I-shaped chromosomes they 

 differ in that they do not have an enlargement in the middle, 

 but rather they have the appearance of a constriction. This 

 constriction is not due to the initiation of the division, for it is 

 present before the chromosomes are arranged on the spindle; 

 in fact, they have their characteristic shape before the spindle 

 is visible. 



The presence of a mass of chromatin in the resting stage of 

 the spermatogonial divisions which is of a different form and 

 different staining capacity and also the presence of a similar mass 

 in the growth period, which can be identified as the accessory 

 chromosome of the spermatocyte, gives added evidence for the 

 continuity of chromosomes as definite entities. 



The spermatozoon of Paratettix leuconotus-leucothorax is very 

 different from the spermatozoon of Paratettix cuculatus as 

 described by Hancock. He describes and figures the head of 

 P. cuculatus as being small, thin, and acutely pointed. In fact, 

 from his figure one would think that the head is very little thicker 

 than the tail. He says that the middle piece is formed into a 



