378 THE CANADIAN ENTOMOLOGIST. 



SOME LITHOBIOMORPHA FROM THE REGION OF SAN 



FRANCISCO BAY. 



BY RALPH V. CHAMBERLIN, PHILADELPHIA, PA. 



Of the six species of the Lithobiomorpha described by Stuxburg from 

 California, the types of four were secured at Sausalito, or near by, on San 

 Francisco Bay. Among these the identification of Lithobiiis kochil and 

 Lithobhis obesiis has been simple j but considerable uncertainty has 

 attached to the forms designated by Stuxberg as Lithohius iiiegaloporiis^ 

 later placed in his subgenus Pseudolithohius, and Lithobtus ptisio, placed 

 by its author in his subgenus Archilithobius^ this difficulty being due to 

 the fact that the types were immature individuals, as I previously showed 

 to be indicated by various points in one description. In order, if possible, 

 to clear up this uncertainty, especially \Yith reference to the species 

 megaloporus^ which seemed to merit generic rank, I took advantage of 

 an opportunity presented in April of this year to make collections at 

 Sausalito and several other points on the San Francisco Bay (Mill Valley, 

 Oakland and Berkeley). Ample material of the species described by 

 Stuxberg, as well as of other species, including several interesting new 

 ones, was secured. 



The anticipations with reference to the species megaloporus and 

 piisio were fulfilled. Stuxberg gives the length of uiegaloporus as 12 mm., 

 whereas that of adults is from 35 to 39 mm. The species must be g/iven 

 separate generic rank, and will stand as Psendolithobius megaloporus. 

 The species ///5/^, as anticipated, proves to belong to the genus Bothro- 

 polys and to have been based upon a young specimen of a distinct 

 species, and not of B. monticola, as was thought possible. B. inoiiticola 

 seems not to occur in the Coast Mts. or region, but to be confined to the 

 Sierras and the country northward, being common in Oregon and Wash- 

 ington. Brief descriptions of these two species are given below. 



Of the new forms discovered quite unexpectedly, the most interesting 

 is BuetJiobhis cojiitigans^ the second species of the genus to become 

 known. Unlike B. oabitus, the type species, the new species shows 

 conspicuous sexual dimorphism. The males are uniformly larger than 

 the females, and are remarkable for the very long and distinctly three- 

 jointed gonopods, differing from those of the female in lacking terminal 

 claws and basal spines. In this regard the species suggests a transition 

 from forms presenting no dimorphism to those such as Lithobiiis, in which 

 it is more marked and the male gonopods mostly small and wart-like and 



November. 1911 



