26 Mr. G. R. Waterhouse on Ilaphidia. 



Percheron, in the number of joints of the maxillary palpi and 

 antennse, a difference very easily accounted for in larvae ; for one 

 person might consider the peduncle at the base of the antennae as 

 a joint, whilst another would consider it as a part of the head. 

 Again, the process at the apex of the antennae, and that at the base 

 of the third joint, might be considered by some as distinct joints, 

 whilst others would not be of this opinion. In these cases one 

 may generally determine by the examination of allied species in 

 which those jDarts become most developed. I have considered the 

 peduncle in this case as a distinct joint, because it is flexible, like 

 the other joints of the antennae, and of the same substance ; the 

 other parts being very indistinct, and the antennae being usually 

 four-jointed in larvae, I have not considered them as joints. But 

 in the number of eyes there is a considerable difference, the in- 

 sect observed by Latreille and myself having two ; whilst that by 

 M. Percheron has seven. In the pupa there is, however, the greatest 

 difference, the one described by the latter being quiescent, that by 

 the former active, or possessing the power of locomotion. At the 

 time of rearing the insect, which was in the year 1827, I did not 

 see the pupa, but found its case attached to the gauze covering of the 

 jar in which the larva was kept : from this circumstance, and knowing 

 that the lar\'a could not have changed in that situation, I was in- 

 duced to form the conjecture that the pupa was an active one. 

 Having, however, lately reared more specimens, and carefully ob- 

 served their metamorphosis, I have discovered that this pupa in 

 some respects approaches the active pupae, although it cannot be 

 strictly considered as such, until immediately before assuming the 

 imago state, when the insect having gained sufficient strength is 



ascertained to be lignivorous. The form, also, of the insect of which we are speaking 

 is different from tliat of the generality of wood-feeding larvae. 



However different the form of insects may be in their perfect state, their larvis, 

 if theip habits be alike, are also similar in general appearance ; and this applies 

 even where they may be of different orders. Compare the larva oi Cossus Ugniperda 

 with that of a Ceramhyx ; again, the larva of Trichiosoma with those of tlie Lepi- 

 doptera. Indeed, the shape of the perfect insect seems to be very little influenced 

 by that of the larva. It is a curious fact, however, that in the larvae which I pos- 

 sess, of two allied genera of the Cerambycidcc, the antennae vary in inverse propor- 

 tion to those of the perfect insects. In Lamia nuhila there are distinct rudimentary 

 antennae; in Acanthocinus cBdiUs the rudiments of antennae can scarcely be traced, 

 while in the perfect state the latter has the longest antennas of any Coleopterous 

 insect found in England. It may also be observed, that although the larva does 

 not influence the shape of the perfect insect, yet the form of the larva is a very good 

 guide to the natural situation of the perfect insect, as regards its arrangement, (that 

 is when they are of the same order,) for the larvae of various groups vary but little 

 among each other. 



