Sbptembee 15, 1922] 



SCIENCE 



309 



me a letter from Hawaii, where an insect pre- 

 sumed to be the same is of economic impor- 

 tance, asking for additional information. Since 

 the matter is one of importance to economic 

 entomologists, it may be worth while to state 

 explicitly why Bouche's name can not be used. 

 I have not seen Bouche's original work (1834), 

 but his whole description is quoted by Signoret. 

 In 1875 Signoret received a mealy-bug on 

 pine-apple, which he described, saying that it 

 was probably Bouche's Coccus bromelics. Since 

 there was already an entirely different Coccus 

 bromelice, published in 1778 (now called 

 Diaspis bromelice), it appears that Bouche's 

 name was in any case unavailable. Signoret, 

 uninfluenced by the homonym, was still in con- 

 siderable doubt as to the identity of his insect, 

 and accordingly gave Bouche's description, so 

 that the reader might form his own opinion. 

 That description is somewhat confusing, but 

 we are told that the fertilized female takes the 

 form of a convex, short, elliptical shield, a 

 little narrower in front. The last abdominal 

 segment is cleft. The females, after an early 

 stage, remain in one place all their lives, un- 

 less one tears them oft'. The insect is common 

 in greenhouses, on various plants. There can, 

 I think, be little doubt that Bouche had before 

 him the Lecaniid Saissetia hemisphcerica (Tar- 

 gioni, 1867) ; surely it was not a mealy-bug. 

 In the Fernald Catalogue of Coccidse there is 

 confused with this Lecanium bromelice Bouche, 

 grey marbled with brown, which Signoret did 

 not undertake to identify. It was probably 

 Lecanium hesperidum (L.). 



Another coecid which seems to need discus- 

 sion is the large Lecaniid of the tulip-tree. Dr. 

 W. E. Britton (Bull. 234, Conn. Agric. Exp. 

 Station) gives a good account of this insect, 

 but eaUs it Toumeyella liriodendri (Gmelin), 

 stating that it was so identified by Sanders, 

 "after a careful study." Gmielin's Coccus 

 liriodendri was based on an account by Dr. 

 John Hill, of London, appearing in the Ham- 

 hurgisches Magazine for 1753. Many years 

 ago I borrowed this work from the Library of 

 Congress, and together with Mr. Pergande 

 went over the description. The account is very 

 vague, and contains some apparently inaccu- 

 rate statements, but it evidently applies to a 



Lecaniid on the tulip-tree. We concluded at 

 the time that it was not possible to reach a 

 definite decision, and were not in favor of dis- 

 placing Cook's name tulipiferce (1878). There 

 is no indication that any one has really recon- 

 sidered this evidence, and I think the scale 

 should stand as Toumeyella. tulipiferce (Cook). 



Sanders {Journ. Economic Entomology, 

 1909, p. 432), adopting Pseudococeus adoni- 

 dum (L.) as the name of the common long- 

 tailed mealy-bug (P. longispinus Targ.), refers 

 to the "good description of the insect in 

 Systema Natures, Ed. XII." The "good de- 

 scription" refers to "linea dorsalis longitu- 

 dinalis elevata . . . area inter lineam dosalem 

 marginemque totidem punctis in seriem longi- 

 tudinalem dispositis . . . cauda bifida," etc. 

 Conceivably this may be Orthezia urticce (L.), 

 but this is guessing. There is not anything to 

 clearly indicate the mealy-bug, and part of the 

 description contradicts suoh a reference. I am 

 in favor of using the oldest names when there 

 is real evidence, or even a satisfactory pre- 

 sumption, in their favor, but when the descrip- 

 tions are inapplicable it is another matter. 



The application of the generic name Coccus 

 L. to the soft scales may have to be reconsid- 

 ered. The original Coccus (the word meaning 

 a ben-y) was the hard round scale of the oak, 

 commonly called Kermes. Under the rules, a 

 good argument can be made for considering 

 Coccus ilicis L. {Kermes ilicis) the type of 

 Coccus, on grounds of tautonomy, but there is 

 room for diversity of opinion. Lecanium pul- 

 chrum King, well redescribed by Marchal 

 (1908), should apparently stand as L. rufulum 

 {Eulecanium alni var. rufulum Ckll.). 



T. D. A. COCKEBELL 



University of Colorado 



THE DETERMINATION OF FAT IN CREAM 



To THE Editor of Science: I noticed in 

 Science for July 7, page 25, an abstract of a 

 paper read before the American Chemical 

 Society by E. G. Mahin and R. H. Carr, en- 

 titled "Errors in the determinaition of fat in 

 cream." 



In 1910, the dairy department of Purdue 

 University, under the direction of Professor 

 0. P. Hunziker, head of the department, made 



