196 [February, 



EXPLANATION OF PLATE III. 



Fig. 1. — Abdomen of Aspidiotus nerii, 9 — about x 200. 



v. s. g., ventral salivary glands. 

 2. — Abdomen of Mytilaspis pomorum, $ — about x 300. 

 3. — Second stage of Leucaspis pini, $ — x 50. 

 4. — Dactylopius citri, $ — about x 20. c, spiracles. 

 5. — Lecanium olece, ? (not adult) — x 40. 



a, thoracic segments ; b, abdominal segments ; c, spiracles. 

 6. — Lecanium olece, adult $ , last five abdominal segments (much magnified). 

 7. — Anogenital ring of Dactylopius citri, $ (much magnified). 

 8. — Dactylopius citri, $ , last five abdominal segments (much magnified). 



Villa Nova de Gaya : 



September, 1888. 



A REJOINDER ON RETINIA POSTICANA, ZETT. 



BY W. WARREN, M.A., F.E.S. 



" A man convinced against his will, 

 Is of his own opinion still." 



It is just because I wish to convince Mr. Barrett with his will, 

 that I am making the accompanying comments on his paper in this 

 month's number of the Ent. Mo. Mag. (p. 181), and I will take the 

 question of Zetterstedt's posticana first. I have not the least doubt 

 in my own mind that Zetterstedt's insect, whether specifically distinct 

 from turionella, L., or not, is identical with what Mr. Barrett calls the 

 Scotch form of it: if either Mr. Barrett or dame Nature herself can 

 squeeze another intermediate species in here, it will be a very tight 

 fit. After quoting Heinemann's distinctions, Mr. Barrett says " the 

 two forms are proportionately most accurately the same in shape of 

 fore- and hind-wings." Now, if he will measure the distance from 

 the anal angle of the fore-wing of turionella to the nearest point of 

 the costa, reckoning this distance as the width of the wing, he will, I 

 think, find that the average turionella is quite three times as long as 

 broad in the fore-wing, and posticana not more than two and a half 

 times : to my eyes the greater comparative length in turionella is 

 evident at a glance ; and when Heinemann states that the hind-wings 

 are narrower and more pointed in turionella, he should have added 

 " in proportion to their breadth." Similarly the greater proportionate 

 length of costa in the fore-wing seems to have given him the idea that' 

 it w r as actually straighter, which it certainly is not. In the hiud-wing, 

 however, the sinuous indentation below the apex in turionella is, pace 

 Mr. Barrett, decidedly greater, thus making the apex appear more 

 pointed, and by reason of its greater comparative length making the 

 whole hind-wing appear narrower. 



