58 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



species for the host. He reasoned that the coccid was so re- 

 stricted to its host on account of its sedentary habit, and was so 

 absolutely dependent upon the host for its entire food supply, 

 that each tree or plant must bear a distinct species of scale in- 

 sect, sustained by one particular form of plant sap. Conse- 

 quently Dr. Fitch's notes record forty-one supposed species of 

 the genus Lccanimn. 



It is now well known that many species of scale insects have 

 a great range of food plants of widely divergent orders, while 

 some are quite restricted in habit. It is also known that the 

 size, shape, and color of scale insects are considerably altered 

 by transference from one food plant to another. 



DISCUSSION. 



Fitch recognized but four genera of Coccidae, viz, Dorthesia, 

 Coccus, Lecanium, and Aspidiotus. Under these genera he 

 described a large number of manuscript species, many of 

 which, fortunately, were never published. In some instances 

 cocoons and egg-masses were mistaken for coccids, as will be 

 noted below. 



DORTHESIA. 



Dorthesia cclastri Fitch MS. and D. riburni Fitch MS. are 

 but the commonly recognized egg-masses of the membracid 

 Enchenopa binotata Say. 



Coccus. 



Fitch included in his genus Coccus auct., Coccus cacti^L,.- 

 Dactylopius coccus Costa; Coccus ado nidum H,.=Pseudococcus 

 adonidum (L. ); and Coccus pinicorticisChermespinicorticis 

 (Fh.), an aphid. 



ASPIDIOTUS. 



Under Aspidiotus Fitch included species of four genera rec- 

 ognized at the present time, viz, Aspidiotus proper, Chion- 

 aspis, Aulacaspis, and Lepidosaphes. Aspidiotus ancylus 

 (Putn.) is represented by three manuscript species; Chionas- 

 pis furfura (Fh.) by two; Ch. pinifoHce (Fh.) by two; Ch. 

 lintneri Comst. and Aulacaspis rosce (Bouche) by one each; 

 and Lepidosaphes ulmi L. by four manuscript species ded- 

 icated respectively to Ulmus, Cornus, Ribes, and Juglans. 



LECANIUM. 



The genus Lecanium has always been a most obscure group 

 to entomologists; a genus in which it was much easier to describe 



