Table 9. Published Records Indicating Dates of Laying
in Different Populations of Coluber constrictor
| Date of Laying | Subspecies | Area | Authority |
| June 9, 1952 | flaviventris | SE Texas | Guidry (1953:50) |
| July 1-2, 1920 | flaviventris | Texas | Ortenburger (1928:183) |
| June 1, 1920 | flaviventris | Texas | Ortenburger (1928:183) |
| June 9, 1926 | flaviventris | Oklahoma | Force (1930:31) |
| June 24, 1926 | flaviventris | Oklahoma | Force (1930:31) |
| July 19, 1928 | flaviventris | Oklahoma | Force (1930:31) |
| July 16 | flaviventris | Oklahoma | Carpenter (1958:114) |
| July 4-5, 1948 | flaviventris | Kansas | Munro (1948:199) |
| July 4, 1948 | flaviventris | Kansas | Munro (1948:199) |
| June 26, 1930 | flaviventris | Ohio | Conant (1938:55) |
| July 3, 1961 | mormon | NW Oregon | Van de Velde, Martan and Risley (1962:212) |
| June 7, 1957 | priapus | S Illinois | Rossman (1960:219) |
| June 19, 1912 | priapus | S Georgia | Wright and Bishop (1915:160) |
| July 10, 1940 | priapus | S Illinois | Cagle (1942:187) |
| July 6 | constrictor | New York | Ditmars (1907:284) |
| June 27-July 5, 1951 | constrictor | Virginia | Werler and McCallion (1951:251) |
| June 5, 1947 | stejnegerianus | S Texas | Auffenberg (1949:54) |
Published records of clutches laid by racers, from which figures used in the foregoing account were obtained, include the following:
C. c. constrictor: 22 (Barbour, 1950:104); 21, 13 (Brimley, 1903:261); 25 (Conant, 1938:55); 8 (Ditmars, 1907:284); 7, 12, 14, 16, 19, 20, 31 (McCauley, 1945:76); 14 (Wright and Wright, 1957:136).
C. c. flaviventris: 7 (Anderson, 1942:210); 22 (Brumwell, 1951:205); 11 (Carpenter, 1958:114); 8, 9, 9 (Force, 1930:31); 10 (Guidry, 1953:50); 18 (Liner, 1949:230); 5, 8, 17 (Marr, 1944:484); 5, 14 (Munro, 1948:199); 13, 19 (Ortenburger, 1928:183); 6, 15 (Tinkle, 1959:195); 15, 19 (Wright and Wright, 1957:141).
C. c. priapus: 20, 21 (Cagle, 1942:187); 7 (Conant, 1938:55); 19 (Rossman, 1960:219); 5, 9, 11, 14 (Wright and Bishop, 1915:160); 16 (Wright and Wright, 1957:147).
C. c. mormon: 13, 9, 8, 5, 5, 5, 4, 4 (Cunningham, 1959:17); 5, 6 (Stebbins, 1954:374); 6 (Van de Velde, Martan and Risley, 1962:212); 3, 6 (Wright and Wright, 1957:144):
C. c. stejnegerianus: 10 (Auffenberg, 1949:54).
In general, the number of eggs in the clutch is proportional to the size of the female producing them. The larger and bulkier females produce more eggs. Geographic trends in number of eggs produced are perhaps controlled by differences in size between different populations; thus, the large eastern constrictor produces nearly three times as many eggs per clutch as does the small western mormon, whereas the centrally located flaviventris is somewhat intermediate in size and in numbers of eggs produced.
In most reptiles growth in length and bulk continues after attainment of sexual maturity. For many kinds including Eumeces fasciatus, Crotaphytus collaris, Cnemidophorus sexlineatus, Agkistrodon contortrix (Fitch, 1954:60; 1956:236; 1958:36; 1960:174), and Sceloporus olivaceus (Blair, 1960:94), it has been shown that the larger and older females in a population produce more offspring than do the smaller and younger individuals. This situation applies in the racer, as shown by the clutches of 52 females correlated with their sizes and presumed ages ([Fig. 17], [Table 10]). The two-year-olds contribute a relatively small quota to the annual brood, partly because their clutches are small, but more especially because many of them fail to attain sexual maturity in time to breed. Many of the female racers that are more than two years old also fail to produce an annual clutch of eggs. The 24-day period May 28 to June 20 inclusive is judged to comprise the period when eggs have generally enlarged sufficiently to be detected in gravid females, but still have not been laid in most instances. In this period, in 1960, 1961 and 1962, ratios of gravid females to those not detectably gravid in several supposed age groups arbitrarily established on the basis of size, were as follows:
| Two-year-olds | 2 gravid, 13 apparently not gravid |
| Three-year-olds | 5 gravid, 4 apparently not gravid |
| Four-year-olds | 3 gravid, 2 apparently not gravid |
| Five-year-olds | 4 gravid, 3 apparently not gravid |
| Six-year-olds (or older) | 8 gravid, 2 apparently not gravid |
Fig. 17. Graph showing number of eggs per clutch, and correlation with supposed age (as deduced from length of body) in female blue racers from the Reservation, Rockefeller Tract, and Harvey County Park.