276 BRITISH LEPIDOPTERA. 



COMPARISON OF N. MICROTIIERIELLA WITH THE ALLIED SPECIES. 

 N. microtlwriella belongs to that section of the genus in which there 

 is a single distinct pale fascia on each of the anterior wings, but the 

 fascia is not brilliantly metallic ; indeed, in this species, the fascia is 

 less shining than in any of the allied species, and it may by this 

 character alone be readily distinguished from N. it/nobilella, N. i>la;/i- 

 colella, N. tityrella and A T . nialella, in all of which the fascia is 

 perceptibly shining. From N. arf/entipedella and N. acetnxae it can be 

 distinguished by the more yellowish colour of the fascia, which is 

 more obliquely placed than in N, acetosae ; at the same time, 

 the size alone of N. aryentiptddU would sufficiently distinguish it 

 from A T . microtheriella, which is certainly the smallest lepidopterous 

 insect at present known (Stainton). -Fletcher notes that imagines of 

 X. potent and X. ftlipendulae are quite as small as those of X. micro- 

 theriella, whilst those of .Y. acetosae are much smaller. In a very 

 long series, Fletcher says that he has not a single X. acetosae as large 

 as his smallest specimen of X. microtheriella. 



EGG-LAYING. The egg is deposited on the underside of a leaf of 

 nut or hornbeam, generally close to a rib, and almost entirely con- 

 cealed by the projection of the rib, and the short hairs to be found on 

 the back of the nut-leaf. It is rather more conspicuous when laid on 

 a leaf of hornbeam. 



MINE. The larva commences its extremely narrow mine, proceeding 

 in a straight line close along a rib, and then turning off at a sharp 

 angle, when it meets another rib ; at times it crosses from one rib to 

 another, its path then being irregular and sinuous ; the excrement 

 forms a slender black line, which gradually becomes thicker, and 

 manifestly formed of individual grains ; it is occasionally interrupted 

 for short distances, but never loses its linear appearance ; the mine 

 appears on either side as a slender whitish-green streak. The larva 

 leaves the mine to pupate (Stainton). Frey writes : " Die Mine ist 

 ein sehr diinner, ausserordentlich langer Gang, in welchem eine sehr 

 feine Kothlinie die Seitenriinder nicht erreicht. In dem Haselblatte 

 verliiuft sie in unregelmassigen Windungen, oft mit einer zweiten und 

 dritten Mine sich kreuzend. In Hainbuchenbliittern dagegen liiuft 

 sie in starken, winkligen Biegungen, z. B. eine Strecke dem Rando 

 entlang, dann dicht neben einer Seitenrippe bin bis zur Mittelrippe, 

 von welcher sie sich dann plotzlich umbiegcnd wieder cntfernen kann " 

 (Die Tineen, etc., p. 886). 



LARVA. Length 1 lines ; very pale amber, with the dorsal vessel 

 dark green, giving, at first sight, the larva a greenish appearance, the 

 7th and 8th abdominal segments reddish ; head pale reddish-brown, 

 the hinder part showing through the prothorax (Stainton). The larva 

 mines with the venter uppermost. 



COMPARISON OF THE LARVAE OF N. MICROTHERIELLA AND N. FLOS- 

 LACTELLA. Sie ist als Raupe und nach der Mine nicht ganz leicht von 

 X. floxlactella zu trennen, mit der sie bei uns gloichzeitig in den 

 Blattern von Corylvt avellana lebt, an deren Unterseite die Eier 

 beider Arten gelegt werden. Die Raupen beider sind blass gelb, aber 

 in veranderlichen Niiancen, mit griinem Darm, welcher dem giinzon 

 Leibo mehr oder weniger einen griinlichen Schein giebt ; im Allge- 

 moinon ist X. microtheriella als Raupe die blasser gefiirbte, namcntlich 

 ist ihr braunlicher Kopf, der manchmal fast farblos wasserhell sein 



