A New Salt Marsh Mealy Bug 



(Eriococcus palustris n.sp.) 



Clifford T. Dodds, University of California 



Introduction. — While making a study of the insects of the salt 

 marshes and brackish waters of the San Francisco Bay region, I 

 chanced to find in considerable numbers, a mealy-bug on the salt- 

 marsh cord-grass {Spartina foliosa Trin.). It occurred on the 

 upper surface of the leaves and generally out of reach of the 

 ordinary high tides. The probable reason why this mealy-bug, as 

 well as the scale, Chinaspis spartinae Comst., occurs almost en- 

 tirely on the upper surface of the leaves is because of the fact that 

 during transpiration, water is given off from the lower surface 

 of the leaf, leaving after evaporation a considerable deposit of salt. 



Type host and locality. — From Spartina foliosa Trin., at Al- 

 monte, Marin Co., California, November, 1921. Found wherever 

 the host is located about the shore of Richardson's Bay, an arm of 

 San Francisco Bay. 



Fig. B. Leaf of host plant Spartina foliosa Trin.; w, Chionaspis spartinae 

 Comst., adult female; x, E. palustris, female before secreting sac; 

 y, sac that has been wet by the tide; z, normal sac. 



Sac. — The natural sac is composed of fluffy white waxy fila- 

 ments (Fig. B, z), which after they have become wet by the tide, 

 and this is usually the case in nature, become a light ashy gray (1) , 

 and have a more or less feltlike texture (Fig. B, y), thus offering 

 great protection, especially for the overwintering young. At the 

 posterior end of the sac there is an obscure opening, plugged with 

 wax filaments, where the young escape. The average length of 

 the sac is 4 mm. for the adult females and somewhat less for the 

 males. 



Adult female. — type — (Fig. A) Body smooth; six cephalotho- 

 racic spines on the dorsum, the two median anterior ones being 

 larger than the other four, all straight, slightly expanded at the 

 base, tapering to a rather blunt apex; eight pairs of very small, 

 blunt, conical, dorso-lateral marginal spines on each side; the 



