1883.] 



207 



young females, as they were round and small, and with but little scale, also only one 

 exuvise ; and the spinnerets are, I think, seldom seen in the As2}idioti until they are 

 adult, or at least, until they have cast their skin twice. 



I observe that Signoret, speaking of his A. ilicis, makes the following observa- 

 tion (Ess. Cochen., p. 98) : " Dans beaucoup d'individus femelles, je n'ai pu voir les 

 plaques de filieres. Cela tient-il k la prepai-ation ou y a-t-il quelques individus 

 anormaux qui n'en prennent pas ?" As far as my own limited experience goes, I 

 find the spinnerets are not seen until the age of the insect is somewhat advanced. 

 If I am right in concluding that Mr. Douglas' specimens were young, this will 

 account for his measurement of the female scale being only half a millimetre, whilst 

 mine measure one millimetre. 



Mr. Douglas tells me that he only made one gathering, in September, 1886, of 

 oak leaves, from the same tree ; some he sent to Dr. Signoret, and some he sent to me. 

 Signoret identified those which he received as being the same as his own — " Les 

 echantillons sur chSne sont Y Aspidiotus zonatus, Frauenf., = Asp. quercus, Sign." 

 (Ent. Mo. Mag., xxiii, p. 151), and I think there is no doubt that those which I 

 received are the same as my own ; we are therefore led to the conclusion that my 

 specimens are the Aspidiotus zonatus, Frauenf., and it may now be desirable to 

 describe the specific characters of the species, as Signoret's description, whilst not 

 vei-y detailed, must necessarily be modified, and Frauenfeld only describes the male. 

 The female scale measures about one millimetre, of a smoky-white colour, and 

 more or less elliptical form. The body of the insect may be seen underneath the 

 scale, the two exuviae lying ti'ansversely with it. Exuvite naked, situated in the 

 centre of the scale. 



The female insect measures rather less than a millimetre, about "9 mm. Form 

 oval, segmentation distinct, with marginate and undulated margin. The last seg- 

 ment shows the following 

 Jf//y §5. ,\ characters (see figure) : — 



Four groups of spinnerets, 

 each consisting of from five 

 to eight. The anterior group 

 is situated so close to, as 

 almost to form one with, the 

 posterior group. There are 

 three pairs of lobes, the first 

 and second pairs being well 

 developed, but the third pair 

 is frequently merely rudi- 

 mentary. The median pair 

 is the largest, rounded at the 

 posterior end, with a notch 

 on the outer lateral margin, but with its inner lateral margin entire. The second 

 pair is not as large as the median pair, but is similar in shape and character, whilst 

 the third pair is inconstant. The bases of tlie lobes seem to extend anteriorly into 

 the body, making it appear longitudinally plicated. These are I think what Prof. 

 Comstock terms " thickenings of tlie body wall," and they are remarkably noticeable 

 in this species, especially if the insect is observed before being thoroughly prepared 

 for microscopical examination. 



