134 



of myriapods in the debris on the forest floor is Spirobolus marginatus 

 Say, taken in Urbana, 111., in the Brownfield woods October 15, 18, 

 and May 23 (many specimens), and in the Cottonwood forest October 

 8 and 13; at White Heath, 111., May 26; at Riverside, 111., August 23; 

 at Tonica, 111., in September; and at Bloomington, 111. This is the 

 common large brown diplopod, our largest myriapod. Another large 

 and abundant species is Fontaria virgimensis Dru. This is largely 

 brown dorsally, with marginal triangular yellow spots, yellow below. 

 A chilopod, Bothropolys multidcntatus Newp., was taken in the 

 Brownfield woods October 18; and in woods at Monticello, 111., in June 

 (M. Waddell), with Otocryptops scxspinosus Say. In the Brownfield 

 woods it was taken October 15 and 18; and here also Polydesmus ser- 

 ratns Say was taken May 23. Callipus lactarius Say was taken in the 

 Cottonwood forest previously mentioned, October 8 from decayed logs, 

 and in the Brownfield woods October 15, associated with Scytonotus 

 gramilatus Say and the chilopod LitJwbius voracior Chamb. (No. 491, 

 C. C. A.). These predaceous kinds must be considered important 

 members of the humus and rotten-log communities, and are somewhat 

 comparable to the predaceous clerid beetles upon the living tree trunks 

 in their influence upon the community. They are, however, very sensi- 

 tive to moisture and live in a humid atmosphere among damp debris. 

 Shelford ('13b) has shown that Fontaria corrugata Wood is very 

 sensitve to moisture. Myriapoda are infested by a number of gre- 

 garine parasites (Ellis, '13, pp. 287-288). 



The following statement by Coville ('14, p. 337) is of much in- 

 terest : "The importance of myriapods, however, as contributing to 

 the formation of leafmold has not been adequately recognized. In 

 the canyon of the Potomac River, above Washington, on the steeper 

 talus slopes, especially those facing northward, the formation of alka- 

 line leafmold is in active progress. . . . Here during all the 

 warm weather the fallen leaves of the mixed hardwood forest are 

 occupied by an army of myriapods, the largest and most abundant 

 being a species known as Spirobolus marginatus. . . . On one 

 occasion a thousand were picked up by Mr. H. S. Barber on an area 

 10 by 100 feet, without disturbing the leaves. On another occasion 

 an area 4 by 20 feet yielded 320 of these myriapods, the leaf litter in 

 this area being carefully searched. Everywhere are evidences of the 

 activity of these animals In the deposits of ground-up leaves and rot- 

 ten wood. Careful measurements of the work of the animals in cap- 

 tivity show that the excrement of the adults amounts to about half 

 a cubic centimeter each per day. It is estimated on the basis of the 

 moist weight of the material that these animals are contributing each 



