Mr. W. Spence on the Pulvilli of Flies. 19 
under the notice of the Society, is in the hope of drawing the 
attention of some of the members to a curious subject, which 
seems to require further investigation, and especially with a mi- 
croscope of high powers; the first points evidently being to 
ascertain, beyond all doubt, both by observations on the polished 
surfaces over which flies and other insects have passed, and on 
the extremities of the hairs lining the pulvilli, that these hairs do 
actually excrete a viscid material, as Mr. Blackwall supposes. 
IV. Observations on the Lamellicorn Genus Cryptodus, and 
its Allies. By J. O. Westwoop, F.L.S., &c. 
[Read Sth July, 1841.] 
Tue genus Cryptodus has been well described by Mr. Mac Leay (by 
whom it was proposed) as the most singular of all the Petalocera, in 
an entomological point of view. Originally placed next Mechidius, 
in the family Trogide, its talented proposer has, in his memoir on the 
Cetoniide, published in Dr. Smith’s African Researches, suggested 
that its more legitimate situation is the family Cetoniide, adjoin- 
ing to Cremastocheilus, a group also possessing dentate maxilla, 
an immense mentum covering the other parts of the mouth, anda 
triangularly dilated basal joint to the antenne ; from this group, 
however, it is distinguished by its corneous dentate mandibles ; 
but as horny mandibles occur in other Cetoniideous insects, Mr. 
Mac Leay states his conviction that Cryptodus belongs to the 
Cetoniide, in the following words: ‘It is now long since that, by 
reflecting on the concealed labrum of Cryptodus, the dilated tri- 
angular shape of its antennze, the horny mandibles and maxille, 
similar in form to those of Macroma and Oplostomus, the large 
mentum closing up the mouth, and concealing the palpi, with its 
naked podex, so different from that of the T'rogide, its depressed 
body, and peculiar structure, I became convinced that I ought to 
have assigned this most curious insect to the family of Cetonide, 
and that it ought to have been placed in the immediate vicinity 
of Cremastocheilus.” —Illustr. Annul. So. Afr. p.17. On the other 
hand, Dr. Burmeister having, in his Genera Insectorum, (sub fam. 
Xylophila,) incidentally introduced the genus Cryptodus under the 
family Dynastide, 1 have been induced to enter into a revision of 
the characters of this genus in comparison with those of the several 
c2 
