OKTMANN : THE CRAWFISJHES OF THE STATE OF PENNSYLVANIA 477 



Here males of tlie first form were abundant, while those of the second form were 

 few and small (between 32 and 48 mm. long). The latter consequently all belonged to 

 the generation of that year. Some of them very likely would have changed into the 

 first form within a short time. The smallest male of the first form was 39 mm. long. 



In addition I have seen specimens from Lake Erie, Lorain County, Ohio (Oberlin 

 Museum) collected May 1, 1892, which demonstrate the presence of males of the 

 first form in spring, and I have received from Mr. E. B. Williamson a couple col- 

 lected September 1, 1901, in Emmet County, Michigan, in the act of copulation. 

 The date is slightly ahead of my earliest date for this act in C. obsaims, but falls 

 into the same general season. All these dates perfectly agree with the rules laid 

 down for C. ohscurus. 



Of C. propinquus sanborni I have collected material only in the early spring and 

 late summer. The specimens observed in spring (April 14 and 28, 1905), in the 

 Tuscarawas drainage, Ohio, correspond entirely to the spring condition of C. obscurm. 

 Generally they have a thick coat of dirt, showing that they have gone through the 

 winter without moulting. Most of the males are of the first form, but a few are of 

 the second form, and these have new shells. A large number of the females have 

 eggs. From Dr. Stei'ki I received a number of newly hatched young, 12-15 mm. 

 long, collected on June 18, 190(), at Dennison, Tuscarawas County, Ohio. Among 

 the specimens collected on August 28 and 29, 1905, in Wetzel and Pleasants 

 Counties, West Virginia, many males of the fii"st form were present, but also a con- 

 siderable number of the second form ; Ijesides, there were a number of small speci- 

 mens of the generation of that year. Among the material of this form from Oberlin, 

 collected September 28, 190.'i, the same was true, and thus in this form al.-<o the 

 known facts agree with what has been observed in the case of C. ubucurus. 



3. Cambanis limosus. 



This is the species on which Andrews (1895 and 1904) made his observations. 

 My own dates, which are supplemented by those collected by Mr. II. Cera and Mr. 

 W. R. McConnell, are comparatively few, but, as fiir as they go, show certiiin 

 discrepancies with Andrews' results, which need attentit)n and explanation. 



The largest number of observations I possess are dated in the month of Septem- 

 ber, when I collected this species at numerous localities in eastern I'ennsylvania, 

 New Jersey, and eastern West Virginia in the yeare 18!)8, 1904, and 19U5. At this 

 time the condition of this species entirely corresponds to that of (.'. ohscitms. Males 

 of the first form are abundant and of all sizes. (Smallest, 37 mm. long, from Stony 

 Brook, Princeton, New Jersey, September 21, 1898, and 40 nun. long, from Cren- 



