Reti'ospective Criticism. 709 



" Note on Mr. Robertson'' s Account of the Goat Moth. — I do not I'ecoUect 

 to have seen it stated before, respecting this insect, that it forms an aperture 

 and ticbe opening into the cocoon, although it, and many other wood-eating 

 larvae, secure their exit, when arrived at the imago state, by eating a passage 

 to the outside of the tree (or nearly so in beetles, which are easily able to gnaw 

 through the remainder). Some cocoons, as, for instance, that of the emperor 

 moth, are internally provided with an apparatus of an elastic nature, which 

 enables the imago to effect its escape without difficulty, Mr. Jesse has given 

 a description and figure of this in his Gleanings of Natural Histoi-y. 



" It is the habit of many moths to deposit eggs although unimpregnated : 

 these are unproductive, except in a few instances, where a single impregnation 

 serves for several generations. Some curious facts on this subject, showing 

 that this remarkable physiological peculiarity exists in other insects than the 

 plant lice, where it has long been known, and where it extends to more than 

 a dozen generations, are to be found in the most recent introductions to 

 entomology.* 



" Mr. Robertson contends for rationality in the proceedings of the larva; 

 but he only shows that the larva adopted the ordinary habits of the species. 

 All the phenomena of animal life must be attributed to instinct alone. 



" The goat moth is found, also, in the larva state, at the roots of trees and 

 plants, which it devours. 



" The following passage from Haworth's rare Lepidoptera Sritannica may 

 also be cited : — ' C'ossus is one of the few lepidopterous insects which possess 

 properties injurious to mankind during the larva state. They do considerable 

 damage to young willow trees, by boring into their trunks in various 

 directions, and feeding upon the wood and pith ; often weakening the tree so 

 much as to cause its easy overthrow from the first storm that attacks it after- 

 wards. (See W. Curtis in Linn. Trans., vol.i. p. 86.} Probably the best 

 mode of preventing this mischief would be to search for and destroy the 

 sluggish females at the end of June ; which, from their large size, would be 

 readily found sticking upon the tree near the infected parts. The larvae of 

 Pyrinus (or Zeuzera se'sculi), and those of several small sphinges (iEgerice), 

 bore into the pith of various trees in a similar manner; but their inferior sizes, 

 and rare occurrence, render them objects of little consequence in an economical 

 point of view. But the larvae of several internal feeding cerambyces make 

 great havoc. See Kirbt/ on Cerambyx (Callldium) violaceus in Li7in. Trans., 

 vol. V. p. 246., &c. 



" It may also be added, and the fact will be serviceable in helping to 

 discover the imago, for the purpose recommended by Mr. Haworth, that, 

 previously to assuming the imago state, the chrysalis pushes itself nearly half 

 out of the tree, through the passage it had previously formed ; so that its 

 exuviae may be seen projecting in such situation, about half an inch of the 

 abdominal portion alone remaining in the tree." 



P. 467. Ime l.,for " male ", read "female." — "Classification." The species 

 is of the family Hepialidae of Stephens. — " Egg." After the word "August," 

 add "introducing them into the crevices of the bark with the ovipositor; 

 which instrument is represented in the figure above, and which is capable of 

 being lengthened much more than there shown." 



P. 468. " Pupa." In relation to the representing of the larva's spinning a 

 thin web, Mr. Westwood has noted that Stephens has stated that it forms a 

 cocoon of chips, as Cossus Ligniperda does. In line 17., for "a row," read 

 " two rows." Mr. Westwood greatly questions the capability of an insect, in 

 the pupa state, " to push hard enough to break away the bark to a sufficient 

 extent to admit the exit of itself in the imago state ;" and he has noted on 



* See some instances noticed in the Magazine of Natural History, vol. viii, 

 p.557. — J^. Z). 



Vol. XII.— No. 81. 3f 



