OF WASHINGTON, VOLUME XII, I'lltl. 59 



new species than to determine the old ones. The difficulties 

 encountered in the study of this genus are increased by the 

 remarkably heavy brown chitinization of the skin of these in- 

 sects. A partial clearing is affected by boiling them in caus- 

 tic potash or soda, then washing, dehydrating in alcohol, and 

 mounting in balsam, but frequently antenna?, legs, and spines 

 are lost during this strenuous preparation, and until the slide 

 preparation is complete its value can not be determined. 



Much confusion and many erroneous determinations have 

 resulted from misconceptions of the earlier work on this group. 

 This misconception is evident not alone in America, but in 

 Europe there have been described many species by early 

 writers who considered as most important the following char- 

 acters in order: the food-plant, color, size, and shape. Six 

 words to three lines without a figure usually sufficed for an 

 original description, and consequently in the absence of the 

 types we are in almost total darkness as to their identity. 



In this connection it is very proper to say that more recent 

 authors, in this day of the efficient compound microscope, 

 have laid too much stress on variations in color, size, and 

 shape while hastening to describe new species. Variation is 

 an important, ever-present factor in Nature's plan, which we 

 must consider carefully in defining and limiting species. 



Prof. Robert Newstead, in his "Monograph of the Coccidse 

 of the British Isles," and Dr. Paul Marchal, in "Notes sur les 

 Cochenilles del' Europe," Ann. Soc. Ent. France, vol. LXXVII, 

 pp. 223-309 (1908), have taken great progressive steps 

 toward the solution of the perplexing problems of early syn- 

 onymy of European species of scale insects. Prof. T. D. A. 

 Cockerell in a letter expressed himself as believing that there 

 were many more accepted names of Lecaniumsthan discovered 

 species. 



Fitch recognized and described in his notes forty-one spe- 

 cies and many varieties of Lecaniums. Eight of these were 

 published as new species, of which two are valid, the remain- 

 ing six species being synonyms of the common European Le- 

 canium rorni Bouche. Seven he determined as American 

 representatives of previously described European species, all 

 of which determinations were erroneous. 



Our common cottony maple scale (Pii/rinur/ci ritis L.) was 

 described in Fitch's notes under twelve names, four of which 

 appeared in print. With but one exception these supposed 

 species were named for their supposed host plants, such as 

 Pyrus, .SW/.v, Rubiis, Acer, f'/nittf, /\/nts< Plalanus., Ribc*, 

 Vitis, Madura (Toxylon}, and Ampelopsis. 



