of Buprestide and Elateride. Wan 
the whole head to be merely a firm framework for the mouth, 
The correctness of this view is generally assumed. Chapuis and 
Candéze concur in it entirely, and even try to support it by an 
additional argument, which I cannot but think is of very doubt- 
ful value—namely, that the head must have soft integuments 
for the purpose of being retracted into the prothorax*. On the 
subject of Goureau’s theory t, according to which the whole of 
the prothorax becomes head, Lacordaire observes that it does 
not deserve refutation, that moreover it has been sufficiently 
refuted by Léon Dukeds and Perris; he considers Erichson’s 
interpretation so decidedly true that he looks upon that of 
Ratzeburg and Léw as an almost inexplicable error (Genera des 
Coléopt. iv. on Oe 
Nevertheless Erichson’s theory offers, as we have seen, insu- 
perable difficulties in a physiological point of view ; and it seems 
to be quite worth our while to try whether the matter may not 
be differently regarded. Let us, then, first of all try to realize 
fully the conditions under which the larve have to exist in the 
interior of the timber, and compare the structure of other larvee 
burrowing in wood, particularly the apod larvee of Cerambycide; 
we shall then soon arrive at two important conclusions. In the 
first place, the mandibles must possess extremely powerful 
flexors, which consequently must be too large to find room in 
the proportionally small part which has hitherto been looked 
upon as forming the whole head in the larvee of Lami and 
Buprestide ; in ‘the second place, the great demands upon the 
power and endurance of these apod larvee cannot be satisfied by 
the strength of the mandibular muscles alone, however great ; 
but power and accuracy in the guidance of the head—that 
is, in the application and pressing of the mouth against the 
timber during the act of burrowing—is required in no less de- 
gree. In these sentences lies the key of the whole complicated 
arrangement. A careful dissection will show, what is sufficiently 
surprising, that no one has hitherto had an accurate idea of the 
real extent, shape, and position of the head in the larva of 
either Lamiz or Buprestide. The fact is, that the protruding 
anterior part of the head is uninterruptedly continued back- 
wards imto a very large skull, which, in the larve of Bupres- 
tidee, is so jarge that it actually reaches the very bottom of the 
prothorax, so that the neck is on a line with the first pair of 
* «En effet, dans ces larves la plaque sous-céphalique, cornée a sa partie 
antérieure, est devenue trés-molle dans le reste de son ¢tendue, parce 
quelle doit se replier sur elle méme pour rentrer avec les parties de la 
bouche dans la gaine que lui forme le prothorax.”’ (Chapuis et Candéze, 
Catal. des Larves de Coléopt. pp. 131, 132.) 
+ Ann. de la Soc. Ent. de Fr. sér. 2. vol. i. p. 26. 
Ann. & Mag. N. Hist. Ser. 3. Vol. xviii. 13 
