274 Mr. J. AY. Dunning on the 



leaves, holding themselves fast by their fore feet, and 

 having the abdomen bent round the leaf. On the leaves 

 were discovered numerous oval greenish - yellow eggs, 

 placed in regular rows side by side ; and on the 1 6th 

 June the first larvfe came out of these eggs, others con- 

 tinued to hatch for about a week, but half the eggs Avere 

 attacked by a fungus and proved unproductive. 



Altogether, from the larvre and pupae (forty, more or 

 less) collected at the Kolkje, Ritsema bred eighteen 

 moths, five males and thirteen females. Of these females, 

 and of five more, captured at the same locality, making 

 eighteen in all, not a single one had fully-developed wings, 

 though amongst them there was some difference observ- 

 able in the extent of development of those organs. 



But on the 3rd July, 1875, Ritsema went again to the 

 Kolkje, and in addition to twenty-six males he found a 

 normally-winged female Acentropiis floating dead upon 

 the water, and soon took four more in the same situation. 

 On careful examination these females were found to agree 

 with Aghina's specimen captured at Huissen. On the 

 8th July he went again to the fishpond, and found more 

 normally-winged females, thirteen in all. Thus far, then, 

 of these females from the same pond, exactly one-half had 

 rudimentary Avings, and the other half were fully Avinged. 



Upon this Ritsema Avrites (p. 92): — "The discovery at 

 the Kolkje of normally-Avinged females which agree Avith 

 A. latipennis, had shaken my faith in the existence of two 

 species Avhich should each have its own form of female, 

 and made me incline to Dunning's view (the existence of 

 one species AAdth tAvo forms of female), a vicAv Avhich AA'^as 

 supported by a thorough examination of all the specimens 

 collected by me, as well males as females, and Avas shared 

 by our Micro-Lepidopterist, P. C. T. Snellen." 



Of the larvEe born in June, from eggs laid by the rudi- 

 mentarily-Avinged females Avhich had come from hibernated 

 larvEe, some Avere fully groAvn in August, and began to 

 spin up, liaAang thus taken about six Aveeks to attain their 

 full size. On the 23rd August a male imago appeared, 

 and on the folloAving day a second male ; and 'these Avere 

 all the moths AAdiich emerofed from that batch of eo:o:s in 

 1875. The rest of the larvge hibernated. The larvse 

 taken out of the pond on the 8th July produced four 

 moths betAveen the 17th August and the 15th September; 

 of these, three Avere males, and one Avas a female Avith 



