42 J. T. PATTERSON AND LELIA T. PORTER. 



process is formed in every cell. If it is of constant occurrence, 

 the period of its existence must be very brief; for at the beginning 

 of the first spermatocyte division, which soon follows, it is entirely 

 absent. 



A similar process has been described for the young spermato- 

 cytes of several different Hymenoptera, but the most careful 

 and detailed work on it is that of Meves ('07) on the honey bee. 

 According to Meves, the process in the bee is formed through the 

 influence of one of the primary centrosomes (" Hauptcentriolen "), 

 which arise by division from the original centrosome of the 

 cell. The process with its centrosome is soon withdrawn into 

 the cell. One of the several secondary centrosomes ("Neben- 

 centriolen") which had previously arisen by division from the 

 primary centrosomes, then participates in the formation of the 

 mitotic figure responsible for the production of the so-called 

 polar body. 



While it is not possible in our material to demonstrate all 

 of these fine points, yet it is highly probable that the cytoplasmic 

 process in the germ cells of Paracopidosomopsis has a similar 

 history to that described by Meves for the germ cells of the bee. 



i 



FIRST MATURATION DIVISION. 



Preparation for the first maturation division is made manifest 

 by changes in the nucleus. It is also made evident by changes 

 in the shape of the cell, especially in the spermatocytes which 

 have early lost their interzonal connections. In cells in which 

 these connections persist up until the end of the growth period, 

 the so-called polar body, or rudimentary second spermatocyte, 

 is budded off from the side of the cell that had recently had the 

 connection. In the other spermatocytes a blunt protrusion arises 

 at one side (Fig. 5), which soon develops into a pointed process 

 (Fig. 6). At the pointed end thus formed there is present a 

 tiny centrosome, from which radiate a number of delicate fibers 

 toward the nucleus. At the opposite, or blunt end of the cell, 

 a similar centrosome with its fibers is also present. 



The most important change in the nucleus concerns the 

 nucleolus, which during the first half of the growth period 

 remains a deeply staining, spherical mass (Figs. 2, 3). A number 



