1S90.] 227 



glands vary in their number. It appears to me tliat a mistake was first made by 

 Bouche, who, finding Eeaumur's species on another plant, that is, on the apple in- 

 stead of on the elm, seems to have taken it for granted that it was a new species, 

 and named it Aspidiotus pomorum,aud perhaps we should recall Signoret's observa- 

 tion with reference to this author (op. cif.,p. 12), " Seulement nous devons faire 

 observer que eet auteiir n'a nuUement cherche a connaitre ce qui avait pu etre fait 

 avant lui." Signoret mentions a difference in the form of the female, when de- 

 scribing M. linearis, Geoff., as ct)mpared with 31. conchiformis, Gmel., but it should 

 be remembered that the insect shrinks very much after having deposited the eggs, 

 and often then appears different in shape to what it appeared before or during 

 gestation. Probably, as Prof. Comstock has shown, the most, if not the only, reliable 

 specific differences are to be found in the marginal modifications of the abdominal 

 segments. 



Signoret also describes, but from one specimen only {op. cit., p. 139), Mytilaspis 

 juglandis, which he considered equal to Aspidiotvs juglandis described by Dr. Asa 

 Fitch, but Professor Comstock has since shown by actual examination, that Fitch's 

 A. juglandis is the same as M. pomorum (2nd Rep. Corn. Un. Ex. St., p. 124), and 

 he mentions that the name of 31. juglandis might be retained for Signoret's species 

 found on the butter-nut, the anterior group of glands consisting of 2, the anterior 

 laterals of 6, and the posterior laterals of 5. But, as I have mentioned, one of the 

 M. pomorum sent me by Mr. Douglas showed 2 glands only in the anterior group, 

 so that in the absence of any other differences, we may perhaps conclude that M. 

 juglandis of Signoret is but another synonym of 31. pomorum. Curtis has described 

 a species {A. conchiformis) that is generally considered to be identical with 31. po- 

 morum, but his fig. 6 (pp. cit.) which he furnishes as representing the insect I almost 

 suspect is that of the second cast skin, and I am led to think this because he mentions 

 that he " looked in vain for a rostrum." But he seems to have figured the real 

 insect of the same species in his fig. 3 (op. cit., p. 676), where evidently he was more 

 fortunate in extracting the insect itself from the scale. I think his figures 2 and 3 

 are the same as his A. conchiformis, and although he mentions them in a description 

 of another species (A. Proteus), he cautiously adds, "I cannot, however, be certain 

 that figs. 2 and 3 may not be the scale and the female inhabitant of some other 

 species." Curtis, writing to Fitch some years afterwards (Fitch, JN^ox. Ins., p. 34, 

 1856), says, "I have carefully examined your specimens. They are identical, awrf 

 are the Coccus arhorum linearis, Geoff., and I believe the Coccus conchiformis, Gmel., 

 which is in that case a synonym." 



There are several other species mentioned by authors which it seems to me 

 cannot be accepted as distinct, judging from the descriptions. For instance : the 

 31. vitis, Goethe, noticed by Mr. Douglas in the Ent. Mo. Mag., vol. ssiii, p. 28, but 

 beyond the question of the number of the " spinnerets " (the grouped glands), there 

 seems nothing to distinguish it from 31. pomorum or 31. linearis. The same may be 

 said of the 31. flara, Targ.-Tozz., described by Signoret (op. cit., p. 96), which seems 

 to have no particular characters that would enable us to distinguish it from 31. 

 linearis. 



The 3Iytilaspis saliceti, Bouche, is mentioned by Targioni-Tozzetti in his 

 Catalogue, 1869, p. 44, without any description, and Bouche's description (Ent. Zeit., 

 1851, p. Ill) of it as Aspidiotui- naliceti is insufficient to recognise it, but Signoret 



