Notices of New Books. 8229 



ceive that regular arrangement of the threads of which the framework 

 is composed. 



" The chrjsalis of this larva is one of that class which serve as useful 

 • iastruments to the moths within them in order to escape from the 

 cocoon when the time for that attempt arrives; that is to say, this 

 chrysalis is one of those which have the back armed with spikes, 

 directed obliquely towards the tail, by means of which, when the moth 

 should escape, it presses forward against the end of the cocoon, and, 

 leaning on these points, which prevent it from slipping backwards, 

 presses so strongly that at length the cocoon breaks and affords a 

 passage to the chr^'salis, which, after protruding its anterior segments, 

 ilself yields to the efforts of the moth, which opens it, disengages itself 

 from it, and thus finds itself liberated both from the chrysalis and the 

 cocoon." 



The only other descriptions I shall cite are selected from the genus 

 Nepticula, and these, equally with those which have preceded, will 

 abundantly support ray observations as to the care which the author 

 has bestowed on every branch of the subject. With regard to the 

 limits of species opinions will and must differ. Mr. Stainton does not 

 view this question under the light thrown on it by the still imperfect 

 theories of isomorphous pairs and dimorphism : this may yet be 

 hoped for; but let us accept with gratitude what is placed at our 

 disposal : no other entomologist living has ever sacrificed so much 

 time and money for what can only be appreciated by the instructed 

 few. 



"Nepticula argentipedella : Mode of Life. — The egg is laid on the 

 under surface of the birch leaf, and very frequently close to one of the 

 lateral ribs. The larva mines a blotch of irregular form, but the 

 commencement is always of a peculiar dark brown, and remains con- 

 spicuous, the remainder of the blotch being only a pale greenish brown ; 

 the excrement is scattered quite irregularly in the mine, and never 

 forms a definite track. When the larva is full fed it comes out on the 

 upper surface of the leaf, and descends to the ground, where it con- 

 structs its dark green cocoon. There seems to be only one brood in 

 the year, the larva occurring at the end of September and in October; 

 in some localities it is excessively abundant. The perfect insect 

 appears at the end of May and beginning of June. 



" Description of the Larva. — Length Sj lines. Pale greenish, dorsal 

 vessel bright green ; head and second segment light brown, the mouth 

 and two lines receding from it reddish brown ; beneath is a row of 

 dark reddish oblong spots down the middle." — (Pp. 212 and 216). 



