. Bulletin. Natural history; Natural history. 388 Illinois Nati'ral History Sirve^- Billetin \'f)l. 33, An. 4 Table 11.—Frequency of occurrence of form I males, females carrying eggs (ovigerous), and females carrying young, in Illinois collections of Orconectes illinolensis. Nui nix-1 Num ber and Perreni of Colletlions with Month Col fctions Form 1 M ales 0\iserous Females Fe maks \\\ h N'ouns March 9 1 50 1 50 0 0 Apiil 2 1 50 1 50 1 50 7 0 0 0 0 1 14 Juiu- •! 0 0 0 0 0 0 .July 4 1 25 0 0 0 0 August 12 0 0 0 0 0 0 Oc toht-r 7 4 57 0 0 0 0 Novembct 1 :i 75 0 0 0 0. Males JxD-I Females 30
. Bulletin. Natural history; Natural history. 388 Illinois Nati'ral History Sirve^- Billetin \'f)l. 33, An. 4 Table 11.—Frequency of occurrence of form I males, females carrying eggs (ovigerous), and females carrying young, in Illinois collections of Orconectes illinolensis. Nui nix-1 Num ber and Perreni of Colletlions with Month Col fctions Form 1 M ales 0\iserous Females Fe maks \\\ h N'ouns March 9 1 50 1 50 0 0 Apiil 2 1 50 1 50 1 50 7 0 0 0 0 1 14 Juiu- •! 0 0 0 0 0 0 .July 4 1 25 0 0 0 0 August 12 0 0 0 0 0 0 Oc toht-r 7 4 57 0 0 0 0 Novembct 1 :i 75 0 0 0 0. Males JxD-I Females 30 mm CL "40" —I 50 Fig. 119.—Size-frequency distribution of Orconectes illinoiensis collected in April and May, which no otliei collections of O. illi- noiensis have been made. Although the specimens cannot now be located and re-examined, it seems likely that they were misidentified O. indianensis. Attempts to collect in Cypress Ditch during this survey produced no Or- conectes. Life History.—Among the 263 speci- mens in the INHS collection, 132 are males and 131 are females. The largest specimen is a CL form II male collected in Ciihbons Creek, Pope County, on 2 May 1972. The largest female, 41.(i mm CL, is from Dutchman Creek, Pope County, collected on 11 October 1971. Form I males collected dining the present survey ranged from ') to mm CL (the largest has a right chela ,').')..') mm ill lc-ng(li) and were collected ill Maicii, Apiil, July, October, and November (Table 11). Brown (1955) ccjllected form I males from July to November. Three females in two collections (Table 11) were ovigerous: a CL female collected on 26 March 1975 with 175 eggs, a CL female collected on 8 April 1978 with 84 eggs, and a CL female collected on the latter date with 110 eggs. Eggs are spherical and a\erage mm in diam- eter. Two females, a CL female collected on 28 April 1976 and a mm CL female collected on 19 May 1973,
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